Add description to file_store cargo metadata

Remove keyword from file_store cargo metadata
2023-03-20 12:45:33 -05:00 · 2023-03-20 12:37:22 -05:00
75 changed files with 7166 additions and 6039 deletions
--- a/.github/workflows/code_coverage.yml
+++ b/.github/workflows/code_coverage.yml
@@ -9,7 +9,7 @@ jobs:
    env:
      RUSTFLAGS: "-Cinstrument-coverage"
      RUSTDOCFLAGS: "-Cinstrument-coverage"
-      LLVM_PROFILE_FILE: "./target/coverage/%p-%m.profraw"
+      LLVM_PROFILE_FILE: "report-%p-%m.profraw"

    steps:
      - name: Checkout
@@ -39,16 +39,14 @@ jobs:
        run: pip install hwi==2.1.1 protobuf==3.20.1
      - name: Test
        run: cargo test --all-features
-      - name: Make coverage directory
-        run: mkdir coverage
      - name: Run grcov
-        run: grcov . --binary-path ./target/debug/ -s . -t lcov --branch --ignore-not-existing --keep-only '**/crates/**' --ignore '**/tests/**' --ignore '**/examples/**' -o ./coverage/lcov.info
+        run: mkdir coverage; grcov . --binary-path ./target/debug/ -s . -t lcov --branch --ignore-not-existing --ignore '/*' -o ./coverage/lcov.info
      - name: Generate HTML coverage report
-        run: genhtml -o coverage-report.html --ignore-errors source ./coverage/lcov.info
-      - name: Coveralls upload
-        uses: coverallsapp/github-action@master
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
+        run: genhtml -o coverage-report.html ./coverage/lcov.info
+          #      - name: Coveralls upload
+          #        uses: coverallsapp/github-action@master
+          #        with:
+          #          github-token: ${{ secrets.GITHUB_TOKEN }}
      - name: Upload artifact
        uses: actions/upload-artifact@v2
        with:
--- a/.github/workflows/cont_integration.yml
+++ b/.github/workflows/cont_integration.yml
@@ -32,34 +32,6 @@ jobs:
      - name: Test
        run: cargo test ${{ matrix.features }}

-  check-no-std:
-    name: Check no_std
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-      - name: Install Rust toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: stable
-          override: true
-          profile: minimal
-          # target: "thumbv6m-none-eabi"
-      - name: Rust Cache
-        uses: Swatinem/rust-cache@v2.2.1
-      - name: Check bdk_chain
-        working-directory: ./crates/chain
-        # TODO "--target thumbv6m-none-eabi" should work but currently does not
-        run: cargo check --no-default-features --features bitcoin/no-std,miniscript/no-std,hashbrown
-      - name: Check bdk
-        working-directory: ./crates/bdk
-        # TODO "--target thumbv6m-none-eabi" should work but currently does not
-        run: cargo check --no-default-features --features bitcoin/no-std,miniscript/no-std,bdk_chain/hashbrown
-      - name: Check esplora
-        working-directory: ./crates/esplora
-        # TODO "--target thumbv6m-none-eabi" should work but currently does not
-        run: cargo check --no-default-features --features bitcoin/no-std,miniscript/no-std,bdk_chain/hashbrown
-
  check-wasm:
    name: Check WASM
    runs-on: ubuntu-20.04
@@ -85,10 +57,10 @@ jobs:
        uses: Swatinem/rust-cache@v2.2.1
      - name: Check bdk
        working-directory: ./crates/bdk
-        run: cargo check --target wasm32-unknown-unknown --no-default-features --features bitcoin/no-std,miniscript/no-std,bdk_chain/hashbrown,dev-getrandom-wasm
+        run: cargo check --target wasm32-unknown-unknown --features dev-getrandom-wasm
      - name: Check esplora
        working-directory: ./crates/esplora
-        run: cargo check --target wasm32-unknown-unknown --no-default-features --features bitcoin/no-std,miniscript/no-std,bdk_chain/hashbrown,async
+        run: cargo check --target wasm32-unknown-unknown --features async --no-default-features

  fmt:
    name: Rust fmt
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -28,7 +28,7 @@ The codebase is maintained using the "contributor workflow" where everyone
 without exception contributes patch proposals using "pull requests". This
 facilitates social contribution, easy testing and peer review.

-To contribute a patch, the workflow is as follows:
+To contribute a patch, the worflow is a as follows:

  1. Fork Repository
  2. Create topic branch
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,9 +4,9 @@ members = [
    "crates/chain",
    "crates/file_store",
    "crates/electrum",
-    "crates/esplora",
-    "example-crates/example_cli",
-    "example-crates/example_electrum",
+    "example-crates/keychain_tracker_electrum",
+    "example-crates/keychain_tracker_esplora",
+    "example-crates/keychain_tracker_example_cli",
    "example-crates/wallet_electrum",
    "example-crates/wallet_esplora",
    "example-crates/wallet_esplora_async",
--- a/crates/bdk/Cargo.toml
+++ b/crates/bdk/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "bdk"
 homepage = "https://bitcoindevkit.org"
-version = "1.0.0-alpha.1"
+version = "1.0.0-alpha.0"
 repository = "https://github.com/bitcoindevkit/bdk"
 documentation = "https://docs.rs/bdk"
 description = "A modern, lightweight, descriptor-based wallet library"
@@ -13,13 +13,13 @@ edition = "2021"
 rust-version = "1.57"

 [dependencies]
-log = "=0.4.18"
+log = "^0.4"
 rand = "^0.8"
-miniscript = { version = "9", features = ["serde"], default-features = false }
-bitcoin = { version = "0.29", features = ["serde", "base64", "rand"], default-features = false }
+miniscript = { version = "9", features = ["serde"] }
+bitcoin = { version = "0.29", features = ["serde", "base64", "rand"] }
 serde = { version = "^1.0", features = ["derive"] }
 serde_json = { version = "^1.0" }
-bdk_chain = { path = "../chain", version = "0.5.0", features = ["miniscript", "serde"], default-features = false }
+bdk_chain = { path = "../chain", version = "0.4.0", features = ["miniscript", "serde"] }

 # Optional dependencies
 hwi = { version = "0.5", optional = true, features = [ "use-miniscript"] }
@@ -29,15 +29,17 @@ bip39 = { version = "1.0.1", optional = true }
 getrandom = "0.2"
 js-sys = "0.3"

+
 [features]
 default = ["std"]
-std = ["bitcoin/std", "miniscript/std", "bdk_chain/std"]
+std = []
 compiler = ["miniscript/compiler"]
 all-keys = ["keys-bip39"]
 keys-bip39 = ["bip39"]
 hardware-signer = ["hwi"]
 test-hardware-signer = ["hardware-signer"]

+
 # This feature is used to run `cargo check` in our CI targeting wasm. It's not recommended
 # for libraries to explicitly include the "getrandom/js" feature, so we only do it when
 # necessary for running our CI. See: https://docs.rs/getrandom/0.2.8/getrandom/#webassembly-support
@@ -50,10 +52,12 @@ env_logger = "0.7"
 base64 = "^0.13"
 assert_matches = "1.5.0"

+
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]

+
 [[example]]
 name = "mnemonic_to_descriptors"
 path = "examples/mnemonic_to_descriptors.rs"
--- a/crates/bdk/src/descriptor/error.rs
+++ b/crates/bdk/src/descriptor/error.rs
@@ -11,8 +11,6 @@

 //! Descriptor errors

-use core::fmt;
-
 /// Errors related to the parsing and usage of descriptors
 #[derive(Debug)]
 pub enum Error {
@@ -53,8 +51,8 @@ impl From<crate::keys::KeyError> for Error {
    }
 }

-impl fmt::Display for Error {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::InvalidHdKeyPath => write!(f, "Invalid HD key path"),
            Self::InvalidDescriptorChecksum => {
--- a/crates/bdk/src/descriptor/policy.rs
+++ b/crates/bdk/src/descriptor/policy.rs
@@ -662,11 +662,11 @@ impl Policy {
                (0..*threshold).collect()
            }
            SatisfiableItem::Multisig { keys, .. } => (0..keys.len()).collect(),
-            _ => HashSet::new(),
+            _ => vec![],
        };
-        let selected: HashSet<_> = match path.get(&self.id) {
-            Some(arr) => arr.iter().copied().collect(),
-            _ => default,
+        let selected = match path.get(&self.id) {
+            Some(arr) => arr,
+            _ => &default,
        };

        match &self.item {
@@ -674,24 +674,14 @@ impl Policy {
                let mapped_req = items
                    .iter()
                    .map(|i| i.get_condition(path))
-                    .collect::<Vec<_>>();
+                    .collect::<Result<Vec<_>, _>>()?;

                // if all the requirements are null we don't care about `selected` because there
                // are no requirements
-                if mapped_req
-                    .iter()
-                    .all(|cond| matches!(cond, Ok(c) if c.is_null()))
-                {
+                if mapped_req.iter().all(Condition::is_null) {
                    return Ok(Condition::default());
                }

-                // make sure all the indexes in the `selected` list are within range
-                for index in &selected {
-                    if *index >= items.len() {
-                        return Err(PolicyError::IndexOutOfRange(*index));
-                    }
-                }
-
                // if we have something, make sure we have enough items. note that the user can set
                // an empty value for this step in case of n-of-n, because `selected` is set to all
                // the elements above
@@ -700,18 +690,23 @@ impl Policy {
                }

                // check the selected items, see if there are conflicting requirements
-                mapped_req
-                    .into_iter()
-                    .enumerate()
-                    .filter(|(index, _)| selected.contains(index))
-                    .try_fold(Condition::default(), |acc, (_, cond)| acc.merge(&cond?))
+                let mut requirements = Condition::default();
+                for item_index in selected {
+                    requirements = requirements.merge(
+                        mapped_req
+                            .get(*item_index)
+                            .ok_or(PolicyError::IndexOutOfRange(*item_index))?,
+                    )?;
+                }
+
+                Ok(requirements)
            }
            SatisfiableItem::Multisig { keys, threshold } => {
                if selected.len() < *threshold {
                    return Err(PolicyError::NotEnoughItemsSelected(self.id.clone()));
                }
-                if let Some(item) = selected.into_iter().find(|&i| i >= keys.len()) {
-                    return Err(PolicyError::IndexOutOfRange(item));
+                if let Some(item) = selected.iter().find(|i| **i >= keys.len()) {
+                    return Err(PolicyError::IndexOutOfRange(*item));
                }

                Ok(Condition::default())
--- a/crates/bdk/src/descriptor/template.rs
+++ b/crates/bdk/src/descriptor/template.rs
@@ -17,7 +17,7 @@
 use bitcoin::util::bip32;
 use bitcoin::Network;

-use miniscript::{Legacy, Segwitv0, Tap};
+use miniscript::{Legacy, Segwitv0};

 use super::{ExtendedDescriptor, IntoWalletDescriptor, KeyMap};
 use crate::descriptor::DescriptorError;
@@ -152,34 +152,6 @@ impl<K: IntoDescriptorKey<Segwitv0>> DescriptorTemplate for P2Wpkh<K> {
    }
 }

-/// P2TR template. Expands to a descriptor `tr(key)`
-///
-/// ## Example
-///
-/// ```
-/// # use bdk::bitcoin::{PrivateKey, Network};
-/// # use bdk::Wallet;
-/// # use bdk::wallet::AddressIndex::New;
-/// use bdk::template::P2TR;
-///
-/// let key =
-///     bitcoin::PrivateKey::from_wif("cTc4vURSzdx6QE6KVynWGomDbLaA75dNALMNyfjh3p8DRRar84Um")?;
-/// let mut wallet = Wallet::new_no_persist(P2TR(key), None, Network::Testnet)?;
-///
-/// assert_eq!(
-///     wallet.get_address(New).to_string(),
-///     "tb1pvjf9t34fznr53u5tqhejz4nr69luzkhlvsdsdfq9pglutrpve2xq7hps46"
-/// );
-/// # Ok::<_, Box<dyn std::error::Error>>(())
-/// ```
-pub struct P2TR<K: IntoDescriptorKey<Tap>>(pub K);
-
-impl<K: IntoDescriptorKey<Tap>> DescriptorTemplate for P2TR<K> {
-    fn build(self, _network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
-        descriptor!(tr(self.0))
-    }
-}
-
 /// BIP44 template. Expands to `pkh(key/44'/{0,1}'/0'/{0,1}/*)`
 ///
 /// Since there are hardened derivation steps, this template requires a private derivable key (generally a `xprv`/`tprv`).
@@ -405,81 +377,6 @@ impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip84Public<K> {
    }
 }

-/// BIP86 template. Expands to `tr(key/86'/{0,1}'/0'/{0,1}/*)`
-///
-/// Since there are hardened derivation steps, this template requires a private derivable key (generally a `xprv`/`tprv`).
-///
-/// See [`Bip86Public`] for a template that can work with a `xpub`/`tpub`.
-///
-/// ## Example
-///
-/// ```
-/// # use std::str::FromStr;
-/// # use bdk::bitcoin::{PrivateKey, Network};
-/// # use bdk::{Wallet,  KeychainKind};
-/// # use bdk::wallet::AddressIndex::New;
-/// use bdk::template::Bip86;
-///
-/// let key = bitcoin::util::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPeZRHk4rTG6orPS2CRNFX3njhUXx5vj9qGog5ZMH4uGReDWN5kCkY3jmWEtWause41CDvBRXD1shKknAMKxT99o9qUTRVC6m")?;
-/// let mut wallet = Wallet::new_no_persist(
-///     Bip86(key.clone(), KeychainKind::External),
-///     Some(Bip86(key, KeychainKind::Internal)),
-///     Network::Testnet,
-/// )?;
-///
-/// assert_eq!(wallet.get_address(New).to_string(), "tb1p5unlj09djx8xsjwe97269kqtxqpwpu2epeskgqjfk4lnf69v4tnqpp35qu");
-/// assert_eq!(wallet.public_descriptor(KeychainKind::External).unwrap().to_string(), "tr([c55b303f/86'/1'/0']tpubDCiHofpEs47kx358bPdJmTZHmCDqQ8qw32upCSxHrSEdeeBs2T5Mq6QMB2ukeMqhNBiyhosBvJErteVhfURPGXPv3qLJPw5MVpHUewsbP2m/0/*)#dkgvr5hm");
-/// # Ok::<_, Box<dyn std::error::Error>>(())
-/// ```
-pub struct Bip86<K: DerivableKey<Tap>>(pub K, pub KeychainKind);
-
-impl<K: DerivableKey<Tap>> DescriptorTemplate for Bip86<K> {
-    fn build(self, network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
-        P2TR(segwit_v1::make_bipxx_private(86, self.0, self.1, network)?).build(network)
-    }
-}
-
-/// BIP86 public template. Expands to `tr(key/{0,1}/*)`
-///
-/// This assumes that the key used has already been derived with `m/86'/0'/0'` for Mainnet or `m/86'/1'/0'` for Testnet.
-///
-/// This template requires the parent fingerprint to populate correctly the metadata of PSBTs.
-///
-/// See [`Bip86`] for a template that does the full derivation, but requires private data
-/// for the key.
-///
-/// ## Example
-///
-/// ```
-/// # use std::str::FromStr;
-/// # use bdk::bitcoin::{PrivateKey, Network};
-/// # use bdk::{Wallet,  KeychainKind};
-/// # use bdk::wallet::AddressIndex::New;
-/// use bdk::template::Bip86Public;
-///
-/// let key = bitcoin::util::bip32::ExtendedPubKey::from_str("tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q")?;
-/// let fingerprint = bitcoin::util::bip32::Fingerprint::from_str("c55b303f")?;
-/// let mut wallet = Wallet::new_no_persist(
-///     Bip86Public(key.clone(), fingerprint, KeychainKind::External),
-///     Some(Bip86Public(key, fingerprint, KeychainKind::Internal)),
-///     Network::Testnet,
-/// )?;
-///
-/// assert_eq!(wallet.get_address(New).to_string(), "tb1pwjp9f2k5n0xq73ecuu0c5njvgqr3vkh7yaylmpqvsuuaafymh0msvcmh37");
-/// assert_eq!(wallet.public_descriptor(KeychainKind::External).unwrap().to_string(), "tr([c55b303f/86'/1'/0']tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q/0/*)#2p65srku");
-/// # Ok::<_, Box<dyn std::error::Error>>(())
-/// ```
-pub struct Bip86Public<K: DerivableKey<Tap>>(pub K, pub bip32::Fingerprint, pub KeychainKind);
-
-impl<K: DerivableKey<Tap>> DescriptorTemplate for Bip86Public<K> {
-    fn build(self, network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
-        P2TR(segwit_v1::make_bipxx_public(
-            86, self.0, self.1, self.2, network,
-        )?)
-        .build(network)
-    }
-}
-
 macro_rules! expand_make_bipxx {
    ( $mod_name:ident, $ctx:ty ) => {
        mod $mod_name {
@@ -546,7 +443,6 @@ macro_rules! expand_make_bipxx {

 expand_make_bipxx!(legacy, Legacy);
 expand_make_bipxx!(segwit_v0, Segwitv0);
-expand_make_bipxx!(segwit_v1, Tap);

 #[cfg(test)]
 mod test {
@@ -559,6 +455,7 @@ mod test {
    use crate::descriptor::{DescriptorError, DescriptorMeta};
    use crate::keys::ValidNetworks;
    use assert_matches::assert_matches;
+    use bitcoin::network::constants::Network::Regtest;
    use miniscript::descriptor::{DescriptorPublicKey, KeyMap};
    use miniscript::Descriptor;

@@ -600,14 +497,11 @@ mod test {
    fn check(
        desc: Result<(Descriptor<DescriptorPublicKey>, KeyMap, ValidNetworks), DescriptorError>,
        is_witness: bool,
-        is_taproot: bool,
        is_fixed: bool,
-        network: Network,
        expected: &[&str],
    ) {
        let (desc, _key_map, _networks) = desc.unwrap();
        assert_eq!(desc.is_witness(), is_witness);
-        assert_eq!(desc.is_taproot(), is_taproot);
        assert_eq!(!desc.has_wildcard(), is_fixed);
        for i in 0..expected.len() {
            let index = i as u32;
@@ -616,7 +510,7 @@ mod test {
            } else {
                desc.at_derivation_index(index)
            };
-            let address = child_desc.address(network).unwrap();
+            let address = child_desc.address(Regtest).unwrap();
            assert_eq!(address.to_string(), *expected.get(i).unwrap());
        }
    }
@@ -630,9 +524,7 @@ mod test {
        check(
            P2Pkh(prvkey).build(Network::Bitcoin),
            false,
-            false,
            true,
-            Network::Regtest,
            &["mwJ8hxFYW19JLuc65RCTaP4v1rzVU8cVMT"],
        );

@@ -643,9 +535,7 @@ mod test {
        check(
            P2Pkh(pubkey).build(Network::Bitcoin),
            false,
-            false,
            true,
-            Network::Regtest,
            &["muZpTpBYhxmRFuCjLc7C6BBDF32C8XVJUi"],
        );
    }
@@ -659,9 +549,7 @@ mod test {
        check(
            P2Wpkh_P2Sh(prvkey).build(Network::Bitcoin),
            true,
-            false,
            true,
-            Network::Regtest,
            &["2NB4ox5VDRw1ecUv6SnT3VQHPXveYztRqk5"],
        );

@@ -672,9 +560,7 @@ mod test {
        check(
            P2Wpkh_P2Sh(pubkey).build(Network::Bitcoin),
            true,
-            false,
            true,
-            Network::Regtest,
            &["2N5LiC3CqzxDamRTPG1kiNv1FpNJQ7x28sb"],
        );
    }
@@ -688,9 +574,7 @@ mod test {
        check(
            P2Wpkh(prvkey).build(Network::Bitcoin),
            true,
-            false,
            true,
-            Network::Regtest,
            &["bcrt1q4525hmgw265tl3drrl8jjta7ayffu6jfcwxx9y"],
        );

@@ -701,42 +585,11 @@ mod test {
        check(
            P2Wpkh(pubkey).build(Network::Bitcoin),
            true,
-            false,
            true,
-            Network::Regtest,
            &["bcrt1qngw83fg8dz0k749cg7k3emc7v98wy0c7azaa6h"],
        );
    }

-    // P2TR `tr(key)`
-    #[test]
-    fn test_p2tr_template() {
-        let prvkey =
-            bitcoin::PrivateKey::from_wif("cTc4vURSzdx6QE6KVynWGomDbLaA75dNALMNyfjh3p8DRRar84Um")
-                .unwrap();
-        check(
-            P2TR(prvkey).build(Network::Bitcoin),
-            false,
-            true,
-            true,
-            Network::Regtest,
-            &["bcrt1pvjf9t34fznr53u5tqhejz4nr69luzkhlvsdsdfq9pglutrpve2xqnwtkqq"],
-        );
-
-        let pubkey = bitcoin::PublicKey::from_str(
-            "03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd",
-        )
-        .unwrap();
-        check(
-            P2TR(pubkey).build(Network::Bitcoin),
-            false,
-            true,
-            true,
-            Network::Regtest,
-            &["bcrt1pw74tdcrxlzn5r8z6ku2vztr86fgq0m245s72mjktf4afwzsf8ugs4evwdf"],
-        );
-    }
-
    // BIP44 `pkh(key/44'/0'/0'/{0,1}/*)`
    #[test]
    fn test_bip44_template() {
@@ -745,8 +598,6 @@ mod test {
            Bip44(prvkey, KeychainKind::External).build(Network::Bitcoin),
            false,
            false,
-            false,
-            Network::Regtest,
            &[
                "n453VtnjDHPyDt2fDstKSu7A3YCJoHZ5g5",
                "mvfrrumXgTtwFPWDNUecBBgzuMXhYM7KRP",
@@ -757,8 +608,6 @@ mod test {
            Bip44(prvkey, KeychainKind::Internal).build(Network::Bitcoin),
            false,
            false,
-            false,
-            Network::Regtest,
            &[
                "muHF98X9KxEzdKrnFAX85KeHv96eXopaip",
                "n4hpyLJE5ub6B5Bymv4eqFxS5KjrewSmYR",
@@ -776,8 +625,6 @@ mod test {
            Bip44Public(pubkey, fingerprint, KeychainKind::External).build(Network::Bitcoin),
            false,
            false,
-            false,
-            Network::Regtest,
            &[
                "miNG7dJTzJqNbFS19svRdTCisC65dsubtR",
                "n2UqaDbCjWSFJvpC84m3FjUk5UaeibCzYg",
@@ -788,8 +635,6 @@ mod test {
            Bip44Public(pubkey, fingerprint, KeychainKind::Internal).build(Network::Bitcoin),
            false,
            false,
-            false,
-            Network::Regtest,
            &[
                "moDr3vJ8wpt5nNxSK55MPq797nXJb2Ru9H",
                "ms7A1Yt4uTezT2XkefW12AvLoko8WfNJMG",
@@ -806,8 +651,6 @@ mod test {
            Bip49(prvkey, KeychainKind::External).build(Network::Bitcoin),
            true,
            false,
-            false,
-            Network::Regtest,
            &[
                "2N9bCAJXGm168MjVwpkBdNt6ucka3PKVoUV",
                "2NDckYkqrYyDMtttEav5hB3Bfw9EGAW5HtS",
@@ -818,8 +661,6 @@ mod test {
            Bip49(prvkey, KeychainKind::Internal).build(Network::Bitcoin),
            true,
            false,
-            false,
-            Network::Regtest,
            &[
                "2NB3pA8PnzJLGV8YEKNDFpbViZv3Bm1K6CG",
                "2NBiX2Wzxngb5rPiWpUiJQ2uLVB4HBjFD4p",
@@ -837,8 +678,6 @@ mod test {
            Bip49Public(pubkey, fingerprint, KeychainKind::External).build(Network::Bitcoin),
            true,
            false,
-            false,
-            Network::Regtest,
            &[
                "2N3K4xbVAHoiTQSwxkZjWDfKoNC27pLkYnt",
                "2NCTQfJ1sZa3wQ3pPseYRHbaNEpC3AquEfX",
@@ -849,8 +688,6 @@ mod test {
            Bip49Public(pubkey, fingerprint, KeychainKind::Internal).build(Network::Bitcoin),
            true,
            false,
-            false,
-            Network::Regtest,
            &[
                "2NF2vttKibwyxigxtx95Zw8K7JhDbo5zPVJ",
                "2Mtmyd8taksxNVWCJ4wVvaiss7QPZGcAJuH",
@@ -867,8 +704,6 @@ mod test {
            Bip84(prvkey, KeychainKind::External).build(Network::Bitcoin),
            true,
            false,
-            false,
-            Network::Regtest,
            &[
                "bcrt1qkmvk2nadgplmd57ztld8nf8v2yxkzmdvwtjf8s",
                "bcrt1qx0v6zgfwe50m4kqc58cqzcyem7ay2sfl3gvqhp",
@@ -879,8 +714,6 @@ mod test {
            Bip84(prvkey, KeychainKind::Internal).build(Network::Bitcoin),
            true,
            false,
-            false,
-            Network::Regtest,
            &[
                "bcrt1qtrwtz00wxl69e5xex7amy4xzlxkaefg3gfdkxa",
                "bcrt1qqqasfhxpkkf7zrxqnkr2sfhn74dgsrc3e3ky45",
@@ -898,8 +731,6 @@ mod test {
            Bip84Public(pubkey, fingerprint, KeychainKind::External).build(Network::Bitcoin),
            true,
            false,
-            false,
-            Network::Regtest,
            &[
                "bcrt1qedg9fdlf8cnnqfd5mks6uz5w4kgpk2prcdvd0h",
                "bcrt1q3lncdlwq3lgcaaeyruynjnlccr0ve0kakh6ana",
@@ -910,8 +741,6 @@ mod test {
            Bip84Public(pubkey, fingerprint, KeychainKind::Internal).build(Network::Bitcoin),
            true,
            false,
-            false,
-            Network::Regtest,
            &[
                "bcrt1qm6wqukenh7guu792lj2njgw9n78cmwsy8xy3z2",
                "bcrt1q694twxtjn4nnrvnyvra769j0a23rllj5c6cgwp",
@@ -919,67 +748,4 @@ mod test {
            ],
        );
    }
-
-    // BIP86 `tr(key/86'/0'/0'/{0,1}/*)`
-    // Used addresses in test vector in https://github.com/bitcoin/bips/blob/master/bip-0086.mediawiki
-    #[test]
-    fn test_bip86_template() {
-        let prvkey = bitcoin::util::bip32::ExtendedPrivKey::from_str("xprv9s21ZrQH143K3GJpoapnV8SFfukcVBSfeCficPSGfubmSFDxo1kuHnLisriDvSnRRuL2Qrg5ggqHKNVpxR86QEC8w35uxmGoggxtQTPvfUu").unwrap();
-        check(
-            Bip86(prvkey, KeychainKind::External).build(Network::Bitcoin),
-            false,
-            true,
-            false,
-            Network::Bitcoin,
-            &[
-                "bc1p5cyxnuxmeuwuvkwfem96lqzszd02n6xdcjrs20cac6yqjjwudpxqkedrcr",
-                "bc1p4qhjn9zdvkux4e44uhx8tc55attvtyu358kutcqkudyccelu0was9fqzwh",
-                "bc1p0d0rhyynq0awa9m8cqrcr8f5nxqx3aw29w4ru5u9my3h0sfygnzs9khxz8",
-            ],
-        );
-        check(
-            Bip86(prvkey, KeychainKind::Internal).build(Network::Bitcoin),
-            false,
-            true,
-            false,
-            Network::Bitcoin,
-            &[
-                "bc1p3qkhfews2uk44qtvauqyr2ttdsw7svhkl9nkm9s9c3x4ax5h60wqwruhk7",
-                "bc1ptdg60grjk9t3qqcqczp4tlyy3z47yrx9nhlrjsmw36q5a72lhdrs9f00nj",
-                "bc1pgcwgsu8naxp7xlp5p7ufzs7emtfza2las7r2e7krzjhe5qj5xz2q88kmk5",
-            ],
-        );
-    }
-
-    // BIP86 public `tr(key/{0,1}/*)`
-    // Used addresses in test vector in https://github.com/bitcoin/bips/blob/master/bip-0086.mediawiki
-    #[test]
-    fn test_bip86_public_template() {
-        let pubkey = bitcoin::util::bip32::ExtendedPubKey::from_str("xpub6BgBgsespWvERF3LHQu6CnqdvfEvtMcQjYrcRzx53QJjSxarj2afYWcLteoGVky7D3UKDP9QyrLprQ3VCECoY49yfdDEHGCtMMj92pReUsQ").unwrap();
-        let fingerprint = bitcoin::util::bip32::Fingerprint::from_str("73c5da0a").unwrap();
-        check(
-            Bip86Public(pubkey, fingerprint, KeychainKind::External).build(Network::Bitcoin),
-            false,
-            true,
-            false,
-            Network::Bitcoin,
-            &[
-                "bc1p5cyxnuxmeuwuvkwfem96lqzszd02n6xdcjrs20cac6yqjjwudpxqkedrcr",
-                "bc1p4qhjn9zdvkux4e44uhx8tc55attvtyu358kutcqkudyccelu0was9fqzwh",
-                "bc1p0d0rhyynq0awa9m8cqrcr8f5nxqx3aw29w4ru5u9my3h0sfygnzs9khxz8",
-            ],
-        );
-        check(
-            Bip86Public(pubkey, fingerprint, KeychainKind::Internal).build(Network::Bitcoin),
-            false,
-            true,
-            false,
-            Network::Bitcoin,
-            &[
-                "bc1p3qkhfews2uk44qtvauqyr2ttdsw7svhkl9nkm9s9c3x4ax5h60wqwruhk7",
-                "bc1ptdg60grjk9t3qqcqczp4tlyy3z47yrx9nhlrjsmw36q5a72lhdrs9f00nj",
-                "bc1pgcwgsu8naxp7xlp5p7ufzs7emtfza2las7r2e7krzjhe5qj5xz2q88kmk5",
-            ],
-        );
-    }
 }
--- a/crates/bdk/src/error.rs
+++ b/crates/bdk/src/error.rs
@@ -107,10 +107,8 @@ impl fmt::Display for MiniscriptPsbtError {
    }
 }

-#[cfg(feature = "std")]
 impl std::error::Error for MiniscriptPsbtError {}

-#[cfg(feature = "std")]
 impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
--- a/crates/bdk/src/keys/mod.rs
+++ b/crates/bdk/src/keys/mod.rs
@@ -15,7 +15,6 @@ use crate::collections::HashSet;
 use alloc::string::{String, ToString};
 use alloc::vec::Vec;
 use core::any::TypeId;
-use core::fmt;
 use core::marker::PhantomData;
 use core::ops::Deref;
 use core::str::FromStr;
@@ -935,8 +934,8 @@ pub enum KeyError {
 impl_error!(miniscript::Error, Miniscript, KeyError);
 impl_error!(bitcoin::util::bip32::Error, Bip32, KeyError);

-impl fmt::Display for KeyError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+impl std::fmt::Display for KeyError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::InvalidScriptContext => write!(f, "Invalid script context"),
            Self::InvalidNetwork => write!(f, "Invalid network"),
--- a/crates/bdk/src/lib.rs
+++ b/crates/bdk/src/lib.rs
@@ -1,13 +1,5 @@
 #![doc = include_str!("../README.md")]
-// only enables the `doc_cfg` feature when the `docsrs` configuration attribute is defined
-#![cfg_attr(docsrs, feature(doc_cfg))]
-#![cfg_attr(
-    docsrs,
-    doc(html_logo_url = "https://github.com/bitcoindevkit/bdk/raw/master/static/bdk.png")
-)]
 #![no_std]
-#![warn(missing_docs)]
-
 #[cfg(feature = "std")]
 #[macro_use]
 extern crate std;
--- a/crates/bdk/src/types.rs
+++ b/crates/bdk/src/types.rs
@@ -22,9 +22,9 @@ use serde::{Deserialize, Serialize};
 /// Types of keychains
 #[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq, Hash, Ord, PartialOrd)]
 pub enum KeychainKind {
-    /// External keychain, used for deriving recipient addresses.
+    /// External
    External = 0,
-    /// Internal keychain, used for deriving change addresses.
+    /// Internal, usually used for change outputs
    Internal = 1,
 }

@@ -114,11 +114,6 @@ impl FeeRate {
        self.0
    }

-    /// Return the value as satoshi/kwu
-    pub fn sat_per_kwu(&self) -> f32 {
-        self.0 * 250.0_f32
-    }
-
    /// Calculate absolute fee in Satoshis using size in weight units.
    pub fn fee_wu(&self, wu: usize) -> u64 {
        self.fee_vb(wu.vbytes())
@@ -334,6 +329,5 @@ mod tests {
    fn test_fee_from_sat_per_kwu() {
        let fee = FeeRate::from_sat_per_kwu(250.0);
        assert!((fee.as_sat_per_vb() - 1.0).abs() < f32::EPSILON);
-        assert_eq!(fee.sat_per_kwu(), 250.0);
    }
 }
--- a/crates/bdk/src/wallet/coin_selection.rs
+++ b/crates/bdk/src/wallet/coin_selection.rs
@@ -722,13 +722,9 @@ mod test {

    fn get_test_utxos() -> Vec<WeightedUtxo> {
        vec![
-            utxo(100_000, 0, ConfirmationTime::Unconfirmed { last_seen: 0 }),
-            utxo(
-                FEE_AMOUNT - 40,
-                1,
-                ConfirmationTime::Unconfirmed { last_seen: 0 },
-            ),
-            utxo(200_000, 2, ConfirmationTime::Unconfirmed { last_seen: 0 }),
+            utxo(100_000, 0, ConfirmationTime::Unconfirmed),
+            utxo(FEE_AMOUNT - 40, 1, ConfirmationTime::Unconfirmed),
+            utxo(200_000, 2, ConfirmationTime::Unconfirmed),
        ]
    }

@@ -784,7 +780,7 @@ mod test {
                            time: rng.next_u64(),
                        }
                    } else {
-                        ConfirmationTime::Unconfirmed { last_seen: 0 }
+                        ConfirmationTime::Unconfirmed
                    },
                }),
            });
@@ -807,7 +803,7 @@ mod test {
                keychain: KeychainKind::External,
                is_spent: false,
                derivation_index: 42,
-                confirmation_time: ConfirmationTime::Unconfirmed { last_seen: 0 },
+                confirmation_time: ConfirmationTime::Unconfirmed,
            }),
        };
        vec![utxo; utxos_number]
@@ -1095,11 +1091,7 @@ mod test {

        let required = vec![utxos[0].clone()];
        let mut optional = utxos[1..].to_vec();
-        optional.push(utxo(
-            500_000,
-            3,
-            ConfirmationTime::Unconfirmed { last_seen: 0 },
-        ));
+        optional.push(utxo(500_000, 3, ConfirmationTime::Unconfirmed));

        // Defensive assertions, for sanity and in case someone changes the test utxos vector.
        let amount: u64 = required.iter().map(|u| u.utxo.txout().value).sum();
--- a/crates/bdk/src/wallet/export.rs
+++ b/crates/bdk/src/wallet/export.rs
@@ -56,6 +56,7 @@
 use core::str::FromStr;

 use alloc::string::{String, ToString};
+use bdk_chain::sparse_chain::ChainPosition;
 use serde::{Deserialize, Serialize};

 use miniscript::descriptor::{ShInner, WshInner};
@@ -129,10 +130,8 @@ impl FullyNodedExport {
            wallet
                .transactions()
                .next()
-                .map_or(0, |canonical_tx| match canonical_tx.observed_as {
-                    bdk_chain::ChainPosition::Confirmed(a) => a.confirmation_height,
-                    bdk_chain::ChainPosition::Unconfirmed(_) => 0,
-                })
+                .and_then(|(pos, _)| pos.height().into())
+                .unwrap_or(0)
        } else {
            0
        };
--- a/crates/bdk/src/wallet/mod.rs
+++ b/crates/bdk/src/wallet/mod.rs
--- a/crates/bdk/src/wallet/tx_builder.rs
+++ b/crates/bdk/src/wallet/tx_builder.rs
@@ -39,7 +39,7 @@
 use crate::collections::BTreeMap;
 use crate::collections::HashSet;
 use alloc::{boxed::Box, rc::Rc, string::String, vec::Vec};
-use bdk_chain::PersistBackend;
+use bdk_chain::ConfirmationTime;
 use core::cell::RefCell;
 use core::marker::PhantomData;

@@ -47,7 +47,7 @@ use bitcoin::util::psbt::{self, PartiallySignedTransaction as Psbt};
 use bitcoin::{LockTime, OutPoint, Script, Sequence, Transaction};

 use super::coin_selection::{CoinSelectionAlgorithm, DefaultCoinSelectionAlgorithm};
-use super::ChangeSet;
+use super::persist;
 use crate::{
    types::{FeeRate, KeychainKind, LocalUtxo, WeightedUtxo},
    TransactionDetails,
@@ -190,9 +190,6 @@ impl<'a, D, Cs: CoinSelectionAlgorithm, Ctx: TxBuilderContext> TxBuilder<'a, D,
    }

    /// Set an absolute fee
-    /// The fee_absolute method refers to the absolute transaction fee in satoshis (sats).
-    /// If anyone sets both the fee_absolute method and the fee_rate method,
-    /// the fee_absolute value will take precedence over the fee_rate.
    pub fn fee_absolute(&mut self, fee_amount: u64) -> &mut Self {
        self.params.fee_policy = Some(FeePolicy::FeeAmount(fee_amount));
        self
@@ -529,7 +526,7 @@ impl<'a, D, Cs: CoinSelectionAlgorithm, Ctx: TxBuilderContext> TxBuilder<'a, D,
    /// [`BIP174`]: https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki
    pub fn finish(self) -> Result<(Psbt, TransactionDetails), Error>
    where
-        D: PersistBackend<ChangeSet>,
+        D: persist::PersistBackend<KeychainKind, ConfirmationTime>,
    {
        self.wallet
            .borrow_mut()
@@ -884,7 +881,7 @@ mod test {
                txout: Default::default(),
                keychain: KeychainKind::External,
                is_spent: false,
-                confirmation_time: ConfirmationTime::Unconfirmed { last_seen: 0 },
+                confirmation_time: ConfirmationTime::Unconfirmed,
                derivation_index: 0,
            },
            LocalUtxo {
--- a/crates/bdk/tests/wallet.rs
+++ b/crates/bdk/tests/wallet.rs
@@ -8,8 +8,8 @@ use bdk::Error;
 use bdk::FeeRate;
 use bdk::KeychainKind;
 use bdk_chain::BlockId;
-use bdk_chain::ConfirmationTime;
 use bdk_chain::COINBASE_MATURITY;
+use bdk_chain::{ConfirmationTime, TxHeight};
 use bitcoin::hashes::Hash;
 use bitcoin::BlockHash;
 use bitcoin::Script;
@@ -23,7 +23,7 @@ use core::str::FromStr;
 mod common;
 use common::*;

-fn receive_output(wallet: &mut Wallet, value: u64, height: ConfirmationTime) -> OutPoint {
+fn receive_output(wallet: &mut Wallet, value: u64, height: TxHeight) -> OutPoint {
    let tx = Transaction {
        version: 1,
        lock_time: PackedLockTime(0),
@@ -34,7 +34,18 @@ fn receive_output(wallet: &mut Wallet, value: u64, height: ConfirmationTime) ->
        }],
    };

-    wallet.insert_tx(tx.clone(), height).unwrap();
+    wallet
+        .insert_tx(
+            tx.clone(),
+            match height {
+                TxHeight::Confirmed(height) => ConfirmationTime::Confirmed {
+                    height,
+                    time: 42_000,
+                },
+                TxHeight::Unconfirmed => ConfirmationTime::Unconfirmed,
+            },
+        )
+        .unwrap();

    OutPoint {
        txid: tx.txid(),
@@ -43,10 +54,7 @@ fn receive_output(wallet: &mut Wallet, value: u64, height: ConfirmationTime) ->
 }

 fn receive_output_in_latest_block(wallet: &mut Wallet, value: u64) -> OutPoint {
-    let height = match wallet.latest_checkpoint() {
-        Some(BlockId { height, .. }) => ConfirmationTime::Confirmed { height, time: 0 },
-        None => ConfirmationTime::Unconfirmed { last_seen: 0 },
-    };
+    let height = wallet.latest_checkpoint().map(|id| id.height).into();
    receive_output(wallet, value, height)
 }

@@ -65,7 +73,7 @@ fn test_descriptor_checksum() {
    assert_eq!(checksum.len(), 8);

    let raw_descriptor = wallet
-        .keychains()
+        .keychanins()
        .iter()
        .next()
        .unwrap()
@@ -803,10 +811,7 @@ fn test_create_tx_add_utxo() {
        lock_time: PackedLockTime(0),
    };
    wallet
-        .insert_tx(
-            small_output_tx.clone(),
-            ConfirmationTime::Unconfirmed { last_seen: 0 },
-        )
+        .insert_tx(small_output_tx.clone(), ConfirmationTime::Unconfirmed)
        .unwrap();

    let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
@@ -843,10 +848,7 @@ fn test_create_tx_manually_selected_insufficient() {
    };

    wallet
-        .insert_tx(
-            small_output_tx.clone(),
-            ConfirmationTime::Unconfirmed { last_seen: 0 },
-        )
+        .insert_tx(small_output_tx.clone(), ConfirmationTime::Unconfirmed)
        .unwrap();

    let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
@@ -887,9 +889,7 @@ fn test_create_tx_policy_path_no_csv() {
            script_pubkey: wallet.get_address(New).script_pubkey(),
        }],
    };
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    let external_policy = wallet.policies(KeychainKind::External).unwrap().unwrap();
    let root_id = external_policy.id;
@@ -925,25 +925,6 @@ fn test_create_tx_policy_path_use_csv() {
    assert_eq!(psbt.unsigned_tx.input[0].sequence, Sequence(144));
 }

-#[test]
-fn test_create_tx_policy_path_ignored_subtree_with_csv() {
-    let (mut wallet, _) = get_funded_wallet("wsh(or_d(pk(cRjo6jqfVNP33HhSS76UhXETZsGTZYx8FMFvR9kpbtCSV1PmdZdu),or_i(and_v(v:pkh(cVpPVruEDdmutPzisEsYvtST1usBR3ntr8pXSyt6D2YYqXRyPcFW),older(30)),and_v(v:pkh(cMnkdebixpXMPfkcNEjjGin7s94hiehAH4mLbYkZoh9KSiNNmqC8),older(90)))))");
-
-    let external_policy = wallet.policies(KeychainKind::External).unwrap().unwrap();
-    let root_id = external_policy.id;
-    // child #0 is pk(cRjo6jqfVNP33HhSS76UhXETZsGTZYx8FMFvR9kpbtCSV1PmdZdu)
-    let path = vec![(root_id, vec![0])].into_iter().collect();
-
-    let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
-    let mut builder = wallet.build_tx();
-    builder
-        .add_recipient(addr.script_pubkey(), 30_000)
-        .policy_path(path, KeychainKind::External);
-    let (psbt, _) = builder.finish().unwrap();
-
-    assert_eq!(psbt.unsigned_tx.input[0].sequence, Sequence(0xFFFFFFFE));
-}
-
 #[test]
 fn test_create_tx_global_xpubs_with_origin() {
    use bitcoin::hashes::hex::FromHex;
@@ -972,7 +953,7 @@ fn test_add_foreign_utxo() {
        get_funded_wallet("wpkh(cVbZ8ovhye9AoAHFsqobCf7LxbXDAECy9Kb8TZdfsDYMZGBUyCnm)");

    let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
-    let utxo = wallet2.list_unspent().next().expect("must take!");
+    let utxo = wallet2.list_unspent().remove(0);
    let foreign_utxo_satisfaction = wallet2
        .get_descriptor_for_keychain(KeychainKind::External)
        .max_satisfaction_weight()
@@ -1036,7 +1017,7 @@ fn test_add_foreign_utxo() {
 #[should_panic(expected = "Generic(\"Foreign utxo missing witness_utxo or non_witness_utxo\")")]
 fn test_add_foreign_utxo_invalid_psbt_input() {
    let (mut wallet, _) = get_funded_wallet(get_test_wpkh());
-    let outpoint = wallet.list_unspent().next().expect("must exist").outpoint;
+    let outpoint = wallet.list_unspent()[0].outpoint;
    let foreign_utxo_satisfaction = wallet
        .get_descriptor_for_keychain(KeychainKind::External)
        .max_satisfaction_weight()
@@ -1054,7 +1035,7 @@ fn test_add_foreign_utxo_where_outpoint_doesnt_match_psbt_input() {
    let (wallet2, txid2) =
        get_funded_wallet("wpkh(cVbZ8ovhye9AoAHFsqobCf7LxbXDAECy9Kb8TZdfsDYMZGBUyCnm)");

-    let utxo2 = wallet2.list_unspent().next().unwrap();
+    let utxo2 = wallet2.list_unspent().remove(0);
    let tx1 = wallet1.get_tx(txid1, true).unwrap().transaction.unwrap();
    let tx2 = wallet2.get_tx(txid2, true).unwrap().transaction.unwrap();

@@ -1098,7 +1079,7 @@ fn test_add_foreign_utxo_only_witness_utxo() {
    let (wallet2, txid2) =
        get_funded_wallet("wpkh(cVbZ8ovhye9AoAHFsqobCf7LxbXDAECy9Kb8TZdfsDYMZGBUyCnm)");
    let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
-    let utxo2 = wallet2.list_unspent().next().unwrap();
+    let utxo2 = wallet2.list_unspent().remove(0);

    let satisfaction_weight = wallet2
        .get_descriptor_for_keychain(KeychainKind::External)
@@ -1214,9 +1195,7 @@ fn test_bump_fee_irreplaceable_tx() {

    let tx = psbt.extract_tx();
    let txid = tx.txid();
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();
    wallet.build_fee_bump(txid).unwrap().finish().unwrap();
 }

@@ -1259,9 +1238,7 @@ fn test_bump_fee_low_fee_rate() {
    let tx = psbt.extract_tx();
    let txid = tx.txid();

-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    let mut builder = wallet.build_fee_bump(txid).unwrap();
    builder.fee_rate(FeeRate::from_sat_per_vb(1.0));
@@ -1282,9 +1259,7 @@ fn test_bump_fee_low_abs() {
    let tx = psbt.extract_tx();
    let txid = tx.txid();

-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    let mut builder = wallet.build_fee_bump(txid).unwrap();
    builder.fee_absolute(10);
@@ -1304,9 +1279,7 @@ fn test_bump_fee_zero_abs() {

    let tx = psbt.extract_tx();
    let txid = tx.txid();
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    let mut builder = wallet.build_fee_bump(txid).unwrap();
    builder.fee_absolute(0);
@@ -1324,9 +1297,7 @@ fn test_bump_fee_reduce_change() {
    let (psbt, original_details) = builder.finish().unwrap();
    let tx = psbt.extract_tx();
    let txid = tx.txid();
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    let mut builder = wallet.build_fee_bump(txid).unwrap();
    builder.fee_rate(FeeRate::from_sat_per_vb(2.5)).enable_rbf();
@@ -1411,9 +1382,7 @@ fn test_bump_fee_reduce_single_recipient() {
    let (psbt, original_details) = builder.finish().unwrap();
    let tx = psbt.extract_tx();
    let txid = tx.txid();
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    let mut builder = wallet.build_fee_bump(txid).unwrap();
    builder
@@ -1444,9 +1413,7 @@ fn test_bump_fee_absolute_reduce_single_recipient() {
    let (psbt, original_details) = builder.finish().unwrap();
    let tx = psbt.extract_tx();
    let txid = tx.txid();
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    let mut builder = wallet.build_fee_bump(txid).unwrap();
    builder
@@ -1502,9 +1469,7 @@ fn test_bump_fee_drain_wallet() {
    let (psbt, original_details) = builder.finish().unwrap();
    let tx = psbt.extract_tx();
    let txid = tx.txid();
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();
    assert_eq!(original_details.sent, 25_000);

    // for the new feerate, it should be enough to reduce the output, but since we specify
@@ -1539,16 +1504,7 @@ fn test_bump_fee_remove_output_manually_selected_only() {
        }],
    };
    wallet
-        .insert_tx(
-            init_tx.clone(),
-            wallet
-                .transactions()
-                .last()
-                .unwrap()
-                .observed_as
-                .cloned()
-                .into(),
-        )
+        .insert_tx(init_tx.clone(), wallet.transactions().last().unwrap().0)
        .unwrap();
    let outpoint = OutPoint {
        txid: init_tx.txid(),
@@ -1565,9 +1521,7 @@ fn test_bump_fee_remove_output_manually_selected_only() {
    let (psbt, original_details) = builder.finish().unwrap();
    let tx = psbt.extract_tx();
    let txid = tx.txid();
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();
    assert_eq!(original_details.sent, 25_000);

    let mut builder = wallet.build_fee_bump(txid).unwrap();
@@ -1589,14 +1543,9 @@ fn test_bump_fee_add_input() {
            value: 25_000,
        }],
    };
-    let pos = wallet
-        .transactions()
-        .last()
-        .unwrap()
-        .observed_as
-        .cloned()
-        .into();
-    wallet.insert_tx(init_tx, pos).unwrap();
+    wallet
+        .insert_tx(init_tx, wallet.transactions().last().unwrap().0)
+        .unwrap();

    let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
    let mut builder = wallet.build_tx().coin_selection(LargestFirstCoinSelection);
@@ -1606,9 +1555,7 @@ fn test_bump_fee_add_input() {
    let (psbt, original_details) = builder.finish().unwrap();
    let tx = psbt.extract_tx();
    let txid = tx.txid();
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    let mut builder = wallet.build_fee_bump(txid).unwrap();
    builder.fee_rate(FeeRate::from_sat_per_vb(50.0));
@@ -1652,9 +1599,7 @@ fn test_bump_fee_absolute_add_input() {
    let (psbt, original_details) = builder.finish().unwrap();
    let tx = psbt.extract_tx();
    let txid = tx.txid();
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    let mut builder = wallet.build_fee_bump(txid).unwrap();
    builder.fee_absolute(6_000);
@@ -1704,9 +1649,7 @@ fn test_bump_fee_no_change_add_input_and_change() {

    let tx = psbt.extract_tx();
    let txid = tx.txid();
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    // now bump the fees without using `allow_shrinking`. the wallet should add an
    // extra input and a change output, and leave the original output untouched
@@ -1762,9 +1705,7 @@ fn test_bump_fee_add_input_change_dust() {
    assert_eq!(tx.input.len(), 1);
    assert_eq!(tx.output.len(), 2);
    let txid = tx.txid();
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    let mut builder = wallet.build_fee_bump(txid).unwrap();
    // We set a fee high enough that during rbf we are forced to add
@@ -1824,7 +1765,7 @@ fn test_bump_fee_force_add_input() {
        txin.witness.push([0x00; P2WPKH_FAKE_WITNESS_SIZE]); // fake signature
    }
    wallet
-        .insert_tx(tx.clone(), ConfirmationTime::Unconfirmed { last_seen: 0 })
+        .insert_tx(tx.clone(), ConfirmationTime::Unconfirmed)
        .unwrap();
    // the new fee_rate is low enough that just reducing the change would be fine, but we force
    // the addition of an extra input with `add_utxo()`
@@ -1879,7 +1820,7 @@ fn test_bump_fee_absolute_force_add_input() {
        txin.witness.push([0x00; P2WPKH_FAKE_WITNESS_SIZE]); // fake signature
    }
    wallet
-        .insert_tx(tx.clone(), ConfirmationTime::Unconfirmed { last_seen: 0 })
+        .insert_tx(tx.clone(), ConfirmationTime::Unconfirmed)
        .unwrap();

    // the new fee_rate is low enough that just reducing the change would be fine, but we force
@@ -1933,19 +1874,13 @@ fn test_bump_fee_unconfirmed_inputs_only() {
    let (psbt, __details) = builder.finish().unwrap();
    // Now we receive one transaction with 0 confirmations. We won't be able to use that for
    // fee bumping, as it's still unconfirmed!
-    receive_output(
-        &mut wallet,
-        25_000,
-        ConfirmationTime::Unconfirmed { last_seen: 0 },
-    );
+    receive_output(&mut wallet, 25_000, TxHeight::Unconfirmed);
    let mut tx = psbt.extract_tx();
    let txid = tx.txid();
    for txin in &mut tx.input {
        txin.witness.push([0x00; P2WPKH_FAKE_WITNESS_SIZE]); // fake signature
    }
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();
    let mut builder = wallet.build_fee_bump(txid).unwrap();
    builder.fee_rate(FeeRate::from_sat_per_vb(25.0));
    builder.finish().unwrap();
@@ -1962,7 +1897,7 @@ fn test_bump_fee_unconfirmed_input() {
    let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
    // We receive a tx with 0 confirmations, which will be used as an input
    // in the drain tx.
-    receive_output(&mut wallet, 25_000, ConfirmationTime::unconfirmed(0));
+    receive_output(&mut wallet, 25_000, TxHeight::Unconfirmed);
    let mut builder = wallet.build_tx();
    builder
        .drain_wallet()
@@ -1974,9 +1909,7 @@ fn test_bump_fee_unconfirmed_input() {
    for txin in &mut tx.input {
        txin.witness.push([0x00; P2WPKH_FAKE_WITNESS_SIZE]); // fake signature
    }
-    wallet
-        .insert_tx(tx, ConfirmationTime::Unconfirmed { last_seen: 0 })
-        .unwrap();
+    wallet.insert_tx(tx, ConfirmationTime::Unconfirmed).unwrap();

    let mut builder = wallet.build_fee_bump(txid).unwrap();
    builder
@@ -2708,7 +2641,7 @@ fn test_taproot_foreign_utxo() {
    let (wallet2, _) = get_funded_wallet(get_test_tr_single_sig());

    let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
-    let utxo = wallet2.list_unspent().next().unwrap();
+    let utxo = wallet2.list_unspent().remove(0);
    let psbt_input = wallet2.get_psbt_input(utxo.clone(), None, false).unwrap();
    let foreign_utxo_satisfaction = wallet2
        .get_descriptor_for_keychain(KeychainKind::External)
--- a/crates/chain/Cargo.toml
+++ b/crates/chain/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "bdk_chain"
-version = "0.5.0"
+version = "0.4.0"
 edition = "2021"
 rust-version = "1.57"
 homepage = "https://bitcoindevkit.org"
@@ -13,19 +13,18 @@ readme = "README.md"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

 [dependencies]
-# For no-std, remember to enable the bitcoin/no-std feature
-bitcoin = { version = "0.29", default-features = false }
+bitcoin = { version = "0.29" }
 serde_crate = { package = "serde", version = "1", optional = true, features = ["derive"] }

 # Use hashbrown as a feature flag to have HashSet and HashMap from it.
 # note version 0.13 breaks outs MSRV.
-hashbrown = { version = "0.11", optional = true, features = ["serde"] }
-miniscript = { version = "9.0.0", optional = true, default-features = false }
+hashbrown = { version = "0.12", optional = true,  features = ["serde"] }
+miniscript = { version = "9.0.0", optional = true  }

 [dev-dependencies]
 rand = "0.8"

 [features]
-default = ["std"]
-std = ["bitcoin/std", "miniscript/std"]
-serde = ["serde_crate", "bitcoin/serde"]
+default = ["std", "miniscript"]
+std = []
+serde = ["serde_crate", "bitcoin/serde" ]
--- a/crates/chain/src/chain_data.rs
+++ b/crates/chain/src/chain_data.rs
@@ -1,45 +1,75 @@
 use bitcoin::{hashes::Hash, BlockHash, OutPoint, TxOut, Txid};

-use crate::{Anchor, COINBASE_MATURITY};
+use crate::{
+    sparse_chain::{self, ChainPosition},
+    COINBASE_MATURITY,
+};

-/// Represents the observed position of some chain data.
-///
-/// The generic `A` should be a [`Anchor`] implementation.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, core::hash::Hash)]
-pub enum ChainPosition<A> {
-    /// The chain data is seen as confirmed, and in anchored by `A`.
-    Confirmed(A),
-    /// The chain data is seen in mempool at this given timestamp.
-    Unconfirmed(u64),
+/// Represents the height at which a transaction is confirmed.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[cfg_attr(
+    feature = "serde",
+    derive(serde::Deserialize, serde::Serialize),
+    serde(crate = "serde_crate")
+)]
+pub enum TxHeight {
+    Confirmed(u32),
+    Unconfirmed,
 }

-impl<A> ChainPosition<A> {
-    /// Returns whether [`ChainPosition`] is confirmed or not.
+impl Default for TxHeight {
+    fn default() -> Self {
+        Self::Unconfirmed
+    }
+}
+
+impl core::fmt::Display for TxHeight {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self {
+            Self::Confirmed(h) => core::write!(f, "confirmed_at({})", h),
+            Self::Unconfirmed => core::write!(f, "unconfirmed"),
+        }
+    }
+}
+
+impl From<Option<u32>> for TxHeight {
+    fn from(opt: Option<u32>) -> Self {
+        match opt {
+            Some(h) => Self::Confirmed(h),
+            None => Self::Unconfirmed,
+        }
+    }
+}
+
+impl From<TxHeight> for Option<u32> {
+    fn from(height: TxHeight) -> Self {
+        match height {
+            TxHeight::Confirmed(h) => Some(h),
+            TxHeight::Unconfirmed => None,
+        }
+    }
+}
+
+impl crate::sparse_chain::ChainPosition for TxHeight {
+    fn height(&self) -> TxHeight {
+        *self
+    }
+
+    fn max_ord_of_height(height: TxHeight) -> Self {
+        height
+    }
+
+    fn min_ord_of_height(height: TxHeight) -> Self {
+        height
+    }
+}
+
+impl TxHeight {
    pub fn is_confirmed(&self) -> bool {
        matches!(self, Self::Confirmed(_))
    }
 }

-impl<A: Clone> ChainPosition<&A> {
-    /// Maps a [`ChainPosition<&A>`] into a [`ChainPosition<A>`] by cloning the contents.
-    pub fn cloned(self) -> ChainPosition<A> {
-        match self {
-            ChainPosition::Confirmed(a) => ChainPosition::Confirmed(a.clone()),
-            ChainPosition::Unconfirmed(last_seen) => ChainPosition::Unconfirmed(last_seen),
-        }
-    }
-}
-
-impl<A: Anchor> ChainPosition<A> {
-    /// Determines the upper bound of the confirmation height.
-    pub fn confirmation_height_upper_bound(&self) -> Option<u32> {
-        match self {
-            ChainPosition::Confirmed(a) => Some(a.confirmation_height_upper_bound()),
-            ChainPosition::Unconfirmed(_) => None,
-        }
-    }
-}
-
 /// Block height and timestamp at which a transaction is confirmed.
 #[derive(Debug, Clone, PartialEq, Eq, Copy, PartialOrd, Ord, core::hash::Hash)]
 #[cfg_attr(
@@ -48,46 +78,47 @@ impl<A: Anchor> ChainPosition<A> {
    serde(crate = "serde_crate")
 )]
 pub enum ConfirmationTime {
-    /// The confirmed variant.
-    Confirmed {
-        /// Confirmation height.
-        height: u32,
-        /// Confirmation time in unix seconds.
-        time: u64,
-    },
-    /// The unconfirmed variant.
-    Unconfirmed {
-        /// The last-seen timestamp in unix seconds.
-        last_seen: u64,
-    },
+    Confirmed { height: u32, time: u64 },
+    Unconfirmed,
+}
+
+impl sparse_chain::ChainPosition for ConfirmationTime {
+    fn height(&self) -> TxHeight {
+        match self {
+            ConfirmationTime::Confirmed { height, .. } => TxHeight::Confirmed(*height),
+            ConfirmationTime::Unconfirmed => TxHeight::Unconfirmed,
+        }
+    }
+
+    fn max_ord_of_height(height: TxHeight) -> Self {
+        match height {
+            TxHeight::Confirmed(height) => Self::Confirmed {
+                height,
+                time: u64::MAX,
+            },
+            TxHeight::Unconfirmed => Self::Unconfirmed,
+        }
+    }
+
+    fn min_ord_of_height(height: TxHeight) -> Self {
+        match height {
+            TxHeight::Confirmed(height) => Self::Confirmed {
+                height,
+                time: u64::MIN,
+            },
+            TxHeight::Unconfirmed => Self::Unconfirmed,
+        }
+    }
 }

 impl ConfirmationTime {
-    /// Construct an unconfirmed variant using the given `last_seen` time in unix seconds.
-    pub fn unconfirmed(last_seen: u64) -> Self {
-        Self::Unconfirmed { last_seen }
-    }
-
-    /// Returns whether [`ConfirmationTime`] is the confirmed variant.
    pub fn is_confirmed(&self) -> bool {
        matches!(self, Self::Confirmed { .. })
    }
 }

-impl From<ChainPosition<ConfirmationTimeAnchor>> for ConfirmationTime {
-    fn from(observed_as: ChainPosition<ConfirmationTimeAnchor>) -> Self {
-        match observed_as {
-            ChainPosition::Confirmed(a) => Self::Confirmed {
-                height: a.confirmation_height,
-                time: a.confirmation_time,
-            },
-            ChainPosition::Unconfirmed(_) => Self::Unconfirmed { last_seen: 0 },
-        }
-    }
-}
-
 /// A reference to a block in the canonical chain.
-#[derive(Debug, Clone, PartialEq, Eq, Copy, PartialOrd, Ord, core::hash::Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Copy, PartialOrd, Ord)]
 #[cfg_attr(
    feature = "serde",
    derive(serde::Deserialize, serde::Serialize),
@@ -130,92 +161,51 @@ impl From<(&u32, &BlockHash)> for BlockId {
    }
 }

-/// An [`Anchor`] implementation that also records the exact confirmation height of the transaction.
-#[derive(Debug, Default, Clone, PartialEq, Eq, Copy, PartialOrd, Ord, core::hash::Hash)]
-#[cfg_attr(
-    feature = "serde",
-    derive(serde::Deserialize, serde::Serialize),
-    serde(crate = "serde_crate")
-)]
-pub struct ConfirmationHeightAnchor {
-    /// The anchor block.
-    pub anchor_block: BlockId,
-
-    /// The exact confirmation height of the transaction.
-    ///
-    /// It is assumed that this value is never larger than the height of the anchor block.
-    pub confirmation_height: u32,
-}
-
-impl Anchor for ConfirmationHeightAnchor {
-    fn anchor_block(&self) -> BlockId {
-        self.anchor_block
-    }
-
-    fn confirmation_height_upper_bound(&self) -> u32 {
-        self.confirmation_height
-    }
-}
-
-/// An [`Anchor`] implementation that also records the exact confirmation time and height of the
-/// transaction.
-#[derive(Debug, Default, Clone, PartialEq, Eq, Copy, PartialOrd, Ord, core::hash::Hash)]
-#[cfg_attr(
-    feature = "serde",
-    derive(serde::Deserialize, serde::Serialize),
-    serde(crate = "serde_crate")
-)]
-pub struct ConfirmationTimeAnchor {
-    /// The anchor block.
-    pub anchor_block: BlockId,
-    /// The confirmation height of the chain data being anchored.
-    pub confirmation_height: u32,
-    /// The confirmation time of the chain data being anchored.
-    pub confirmation_time: u64,
-}
-
-impl Anchor for ConfirmationTimeAnchor {
-    fn anchor_block(&self) -> BlockId {
-        self.anchor_block
-    }
-
-    fn confirmation_height_upper_bound(&self) -> u32 {
-        self.confirmation_height
-    }
-}
 /// A `TxOut` with as much data as we can retrieve about it
-#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
-pub struct FullTxOut<A> {
+#[derive(Debug, Clone, PartialEq)]
+pub struct FullTxOut<I> {
    /// The location of the `TxOut`.
    pub outpoint: OutPoint,
    /// The `TxOut`.
    pub txout: TxOut,
    /// The position of the transaction in `outpoint` in the overall chain.
-    pub chain_position: ChainPosition<A>,
+    pub chain_position: I,
    /// The txid and chain position of the transaction (if any) that has spent this output.
-    pub spent_by: Option<(ChainPosition<A>, Txid)>,
+    pub spent_by: Option<(I, Txid)>,
    /// Whether this output is on a coinbase transaction.
    pub is_on_coinbase: bool,
 }

-impl<A: Anchor> FullTxOut<A> {
-    /// Whether the `txout` is considered mature.
+impl<I: ChainPosition> FullTxOut<I> {
+    /// Whether the utxo is/was/will be spendable at `height`.
    ///
-    /// Depending on the implementation of [`confirmation_height_upper_bound`] in [`Anchor`], this
-    /// method may return false-negatives. In other words, interpretted confirmation count may be
-    /// less than the actual value.
-    ///
-    /// [`confirmation_height_upper_bound`]: Anchor::confirmation_height_upper_bound
-    pub fn is_mature(&self, tip: u32) -> bool {
+    /// It is spendable if it is not an immature coinbase output and no spending tx has been
+    /// confirmed by that height.
+    pub fn is_spendable_at(&self, height: u32) -> bool {
+        if !self.is_mature(height) {
+            return false;
+        }
+
+        if self.chain_position.height() > TxHeight::Confirmed(height) {
+            return false;
+        }
+
+        match &self.spent_by {
+            Some((spending_height, _)) => spending_height.height() > TxHeight::Confirmed(height),
+            None => true,
+        }
+    }
+
+    pub fn is_mature(&self, height: u32) -> bool {
        if self.is_on_coinbase {
-            let tx_height = match &self.chain_position {
-                ChainPosition::Confirmed(anchor) => anchor.confirmation_height_upper_bound(),
-                ChainPosition::Unconfirmed(_) => {
+            let tx_height = match self.chain_position.height() {
+                TxHeight::Confirmed(tx_height) => tx_height,
+                TxHeight::Unconfirmed => {
                    debug_assert!(false, "coinbase tx can never be unconfirmed");
                    return false;
                }
            };
-            let age = tip.saturating_sub(tx_height);
+            let age = height.saturating_sub(tx_height);
            if age + 1 < COINBASE_MATURITY {
                return false;
            }
@@ -223,36 +213,6 @@ impl<A: Anchor> FullTxOut<A> {

        true
    }
-
-    /// Whether the utxo is/was/will be spendable with chain `tip`.
-    ///
-    /// This method does not take into account the locktime.
-    ///
-    /// Depending on the implementation of [`confirmation_height_upper_bound`] in [`Anchor`], this
-    /// method may return false-negatives. In other words, interpretted confirmation count may be
-    /// less than the actual value.
-    ///
-    /// [`confirmation_height_upper_bound`]: Anchor::confirmation_height_upper_bound
-    pub fn is_confirmed_and_spendable(&self, tip: u32) -> bool {
-        if !self.is_mature(tip) {
-            return false;
-        }
-
-        let confirmation_height = match &self.chain_position {
-            ChainPosition::Confirmed(anchor) => anchor.confirmation_height_upper_bound(),
-            ChainPosition::Unconfirmed(_) => return false,
-        };
-        if confirmation_height > tip {
-            return false;
-        }
-
-        // if the spending tx is confirmed within tip height, the txout is no longer spendable
-        if let Some((ChainPosition::Confirmed(spending_anchor), _)) = &self.spent_by {
-            if spending_anchor.anchor_block().height <= tip {
-                return false;
-            }
-        }
-
-        true
-    }
 }
+
+// TODO: make test
--- a/crates/chain/src/chain_graph.rs
+++ b/crates/chain/src/chain_graph.rs
@@ -0,0 +1,639 @@
+//! Module for structures that combine the features of [`sparse_chain`] and [`tx_graph`].
+use crate::{
+    collections::HashSet,
+    sparse_chain::{self, ChainPosition, SparseChain},
+    tx_graph::{self, TxGraph},
+    BlockId, ForEachTxOut, FullTxOut, TxHeight,
+};
+use alloc::{string::ToString, vec::Vec};
+use bitcoin::{OutPoint, Transaction, TxOut, Txid};
+use core::fmt::Debug;
+
+/// A consistent combination of a [`SparseChain<P>`] and a [`TxGraph<T>`].
+///
+/// `SparseChain` only keeps track of transaction ids and their position in the chain, but you often
+/// want to store the full transactions as well. Additionally, you want to make sure that everything
+/// in the chain is consistent with the full transaction data. `ChainGraph` enforces these two
+/// invariants:
+///
+/// 1. Every transaction that is in the chain is also in the graph (you always have the full
+/// transaction).
+/// 2. No transactions in the chain conflict with each other, i.e., they don't double spend each
+/// other or have ancestors that double spend each other.
+///
+/// Note that the `ChainGraph` guarantees a 1:1 mapping between transactions in the `chain` and
+/// `graph` but not the other way around. Transactions may fall out of the *chain* (via re-org or
+/// mempool eviction) but will remain in the *graph*.
+#[derive(Clone, Debug, PartialEq)]
+pub struct ChainGraph<P = TxHeight> {
+    chain: SparseChain<P>,
+    graph: TxGraph,
+}
+
+impl<P> Default for ChainGraph<P> {
+    fn default() -> Self {
+        Self {
+            chain: Default::default(),
+            graph: Default::default(),
+        }
+    }
+}
+
+impl<P> AsRef<SparseChain<P>> for ChainGraph<P> {
+    fn as_ref(&self) -> &SparseChain<P> {
+        &self.chain
+    }
+}
+
+impl<P> AsRef<TxGraph> for ChainGraph<P> {
+    fn as_ref(&self) -> &TxGraph {
+        &self.graph
+    }
+}
+
+impl<P> AsRef<ChainGraph<P>> for ChainGraph<P> {
+    fn as_ref(&self) -> &ChainGraph<P> {
+        self
+    }
+}
+
+impl<P> ChainGraph<P> {
+    /// Returns a reference to the internal [`SparseChain`].
+    pub fn chain(&self) -> &SparseChain<P> {
+        &self.chain
+    }
+
+    /// Returns a reference to the internal [`TxGraph`].
+    pub fn graph(&self) -> &TxGraph {
+        &self.graph
+    }
+}
+
+impl<P> ChainGraph<P>
+where
+    P: ChainPosition,
+{
+    /// Create a new chain graph from a `chain` and a `graph`.
+    ///
+    /// There are two reasons this can return an `Err`:
+    ///
+    /// 1. There is a transaction in the `chain` that does not have its corresponding full
+    /// transaction in `graph`.
+    /// 2. The `chain` has two transactions that are allegedly in it, but they conflict in the `graph`
+    /// (so could not possibly be in the same chain).
+    pub fn new(chain: SparseChain<P>, graph: TxGraph) -> Result<Self, NewError<P>> {
+        let mut missing = HashSet::default();
+        for (pos, txid) in chain.txids() {
+            if let Some(tx) = graph.get_tx(*txid) {
+                let conflict = graph
+                    .walk_conflicts(tx, |_, txid| Some((chain.tx_position(txid)?.clone(), txid)))
+                    .next();
+                if let Some((conflict_pos, conflict)) = conflict {
+                    return Err(NewError::Conflict {
+                        a: (pos.clone(), *txid),
+                        b: (conflict_pos, conflict),
+                    });
+                }
+            } else {
+                missing.insert(*txid);
+            }
+        }
+
+        if !missing.is_empty() {
+            return Err(NewError::Missing(missing));
+        }
+
+        Ok(Self { chain, graph })
+    }
+
+    /// Take an update in the form of a [`SparseChain<P>`][`SparseChain`] and attempt to turn it
+    /// into a chain graph by filling in full transactions from `self` and from `new_txs`. This
+    /// returns a `ChainGraph<P, Cow<T>>` where the [`Cow<'a, T>`] will borrow the transaction if it
+    /// got it from `self`.
+    ///
+    /// This is useful when interacting with services like an electrum server which returns a list
+    /// of txids and heights when calling [`script_get_history`], which can easily be inserted into a
+    /// [`SparseChain<TxHeight>`][`SparseChain`]. From there, you need to figure out which full
+    /// transactions you are missing in your chain graph and form `new_txs`. You then use
+    /// `inflate_update` to turn this into an update `ChainGraph<P, Cow<Transaction>>` and finally
+    /// use [`determine_changeset`] to generate the changeset from it.
+    ///
+    /// [`SparseChain`]: crate::sparse_chain::SparseChain
+    /// [`Cow<'a, T>`]: std::borrow::Cow
+    /// [`script_get_history`]: https://docs.rs/electrum-client/latest/electrum_client/trait.ElectrumApi.html#tymethod.script_get_history
+    /// [`determine_changeset`]: Self::determine_changeset
+    pub fn inflate_update(
+        &self,
+        update: SparseChain<P>,
+        new_txs: impl IntoIterator<Item = Transaction>,
+    ) -> Result<ChainGraph<P>, NewError<P>> {
+        let mut inflated_chain = SparseChain::default();
+        let mut inflated_graph = TxGraph::default();
+
+        for (height, hash) in update.checkpoints().clone().into_iter() {
+            let _ = inflated_chain
+                .insert_checkpoint(BlockId { height, hash })
+                .expect("must insert");
+        }
+
+        // [TODO] @evanlinjin: These need better comments
+        // - copy transactions that have changed positions into the graph
+        // - add new transactions to an inflated chain
+        for (pos, txid) in update.txids() {
+            match self.chain.tx_position(*txid) {
+                Some(original_pos) => {
+                    if original_pos != pos {
+                        let tx = self
+                            .graph
+                            .get_tx(*txid)
+                            .expect("tx must exist as it is referenced in sparsechain")
+                            .clone();
+                        let _ = inflated_chain
+                            .insert_tx(*txid, pos.clone())
+                            .expect("must insert since this was already in update");
+                        let _ = inflated_graph.insert_tx(tx);
+                    }
+                }
+                None => {
+                    let _ = inflated_chain
+                        .insert_tx(*txid, pos.clone())
+                        .expect("must insert since this was already in update");
+                }
+            }
+        }
+
+        for tx in new_txs {
+            let _ = inflated_graph.insert_tx(tx);
+        }
+
+        ChainGraph::new(inflated_chain, inflated_graph)
+    }
+
+    /// Gets the checkpoint limit.
+    ///
+    /// Refer to [`SparseChain::checkpoint_limit`] for more.
+    pub fn checkpoint_limit(&self) -> Option<usize> {
+        self.chain.checkpoint_limit()
+    }
+
+    /// Sets the checkpoint limit.
+    ///
+    /// Refer to [`SparseChain::set_checkpoint_limit`] for more.
+    pub fn set_checkpoint_limit(&mut self, limit: Option<usize>) {
+        self.chain.set_checkpoint_limit(limit)
+    }
+
+    /// Determines the changes required to invalidate checkpoints `from_height` (inclusive) and
+    /// above. Displaced transactions will have their positions moved to [`TxHeight::Unconfirmed`].
+    pub fn invalidate_checkpoints_preview(&self, from_height: u32) -> ChangeSet<P> {
+        ChangeSet {
+            chain: self.chain.invalidate_checkpoints_preview(from_height),
+            ..Default::default()
+        }
+    }
+
+    /// Invalidate checkpoints `from_height` (inclusive) and above. Displaced transactions will be
+    /// re-positioned to [`TxHeight::Unconfirmed`].
+    ///
+    /// This is equivalent to calling [`Self::invalidate_checkpoints_preview`] and
+    /// [`Self::apply_changeset`] in sequence.
+    pub fn invalidate_checkpoints(&mut self, from_height: u32) -> ChangeSet<P>
+    where
+        ChangeSet<P>: Clone,
+    {
+        let changeset = self.invalidate_checkpoints_preview(from_height);
+        self.apply_changeset(changeset.clone());
+        changeset
+    }
+
+    /// Get a transaction currently in the underlying [`SparseChain`].
+    ///
+    /// This does not necessarily mean that it is *confirmed* in the blockchain; it might just be in
+    /// the unconfirmed transaction list within the [`SparseChain`].
+    pub fn get_tx_in_chain(&self, txid: Txid) -> Option<(&P, &Transaction)> {
+        let position = self.chain.tx_position(txid)?;
+        let full_tx = self.graph.get_tx(txid).expect("must exist");
+        Some((position, full_tx))
+    }
+
+    /// Determines the changes required to insert a transaction into the inner [`ChainGraph`] and
+    /// [`SparseChain`] at the given `position`.
+    ///
+    /// If inserting it into the chain `position` will result in conflicts, the returned
+    /// [`ChangeSet`] should evict conflicting transactions.
+    pub fn insert_tx_preview(
+        &self,
+        tx: Transaction,
+        pos: P,
+    ) -> Result<ChangeSet<P>, InsertTxError<P>> {
+        let mut changeset = ChangeSet {
+            chain: self.chain.insert_tx_preview(tx.txid(), pos)?,
+            graph: self.graph.insert_tx_preview(tx),
+        };
+        self.fix_conflicts(&mut changeset)?;
+        Ok(changeset)
+    }
+
+    /// Inserts [`Transaction`] at the given chain position.
+    ///
+    /// This is equivalent to calling [`Self::insert_tx_preview`] and [`Self::apply_changeset`] in
+    /// sequence.
+    pub fn insert_tx(&mut self, tx: Transaction, pos: P) -> Result<ChangeSet<P>, InsertTxError<P>> {
+        let changeset = self.insert_tx_preview(tx, pos)?;
+        self.apply_changeset(changeset.clone());
+        Ok(changeset)
+    }
+
+    /// Determines the changes required to insert a [`TxOut`] into the internal [`TxGraph`].
+    pub fn insert_txout_preview(&self, outpoint: OutPoint, txout: TxOut) -> ChangeSet<P> {
+        ChangeSet {
+            chain: Default::default(),
+            graph: self.graph.insert_txout_preview(outpoint, txout),
+        }
+    }
+
+    /// Inserts a [`TxOut`] into the internal [`TxGraph`].
+    ///
+    /// This is equivalent to calling [`Self::insert_txout_preview`] and [`Self::apply_changeset`]
+    /// in sequence.
+    pub fn insert_txout(&mut self, outpoint: OutPoint, txout: TxOut) -> ChangeSet<P> {
+        let changeset = self.insert_txout_preview(outpoint, txout);
+        self.apply_changeset(changeset.clone());
+        changeset
+    }
+
+    /// Determines the changes required to insert a `block_id` (a height and block hash) into the
+    /// chain.
+    ///
+    /// If a checkpoint with a different hash already exists at that height, this will return an error.
+    pub fn insert_checkpoint_preview(
+        &self,
+        block_id: BlockId,
+    ) -> Result<ChangeSet<P>, InsertCheckpointError> {
+        self.chain
+            .insert_checkpoint_preview(block_id)
+            .map(|chain_changeset| ChangeSet {
+                chain: chain_changeset,
+                ..Default::default()
+            })
+    }
+
+    /// Inserts checkpoint into [`Self`].
+    ///
+    /// This is equivalent to calling [`Self::insert_checkpoint_preview`] and
+    /// [`Self::apply_changeset`] in sequence.
+    pub fn insert_checkpoint(
+        &mut self,
+        block_id: BlockId,
+    ) -> Result<ChangeSet<P>, InsertCheckpointError> {
+        let changeset = self.insert_checkpoint_preview(block_id)?;
+        self.apply_changeset(changeset.clone());
+        Ok(changeset)
+    }
+
+    /// Calculates the difference between self and `update` in the form of a [`ChangeSet`].
+    pub fn determine_changeset(
+        &self,
+        update: &ChainGraph<P>,
+    ) -> Result<ChangeSet<P>, UpdateError<P>> {
+        let chain_changeset = self
+            .chain
+            .determine_changeset(&update.chain)
+            .map_err(UpdateError::Chain)?;
+
+        let mut changeset = ChangeSet {
+            chain: chain_changeset,
+            graph: self.graph.determine_additions(&update.graph),
+        };
+
+        self.fix_conflicts(&mut changeset)?;
+        Ok(changeset)
+    }
+
+    /// Given a transaction, return an iterator of `txid`s that conflict with it (spends at least
+    /// one of the same inputs). This iterator includes all descendants of conflicting transactions.
+    ///
+    /// This method only returns conflicts that exist in the [`SparseChain`] as transactions that
+    /// are not included in [`SparseChain`] are already considered as evicted.
+    pub fn tx_conflicts_in_chain<'a>(
+        &'a self,
+        tx: &'a Transaction,
+    ) -> impl Iterator<Item = (&'a P, Txid)> + 'a {
+        self.graph.walk_conflicts(tx, move |_, conflict_txid| {
+            self.chain
+                .tx_position(conflict_txid)
+                .map(|conflict_pos| (conflict_pos, conflict_txid))
+        })
+    }
+
+    /// Fix changeset conflicts.
+    ///
+    /// **WARNING:** If there are any missing full txs, conflict resolution will not be complete. In
+    /// debug mode, this will result in panic.
+    fn fix_conflicts(&self, changeset: &mut ChangeSet<P>) -> Result<(), UnresolvableConflict<P>> {
+        let mut chain_conflicts = vec![];
+
+        for (&txid, pos_change) in &changeset.chain.txids {
+            let pos = match pos_change {
+                Some(pos) => {
+                    // Ignore txs that are still in the chain -- we only care about new ones
+                    if self.chain.tx_position(txid).is_some() {
+                        continue;
+                    }
+                    pos
+                }
+                // Ignore txids that are being deleted by the change (they can't conflict)
+                None => continue,
+            };
+
+            let mut full_tx = self.graph.get_tx(txid);
+
+            if full_tx.is_none() {
+                full_tx = changeset.graph.tx.iter().find(|tx| tx.txid() == txid)
+            }
+
+            debug_assert!(full_tx.is_some(), "should have full tx at this point");
+
+            let full_tx = match full_tx {
+                Some(full_tx) => full_tx,
+                None => continue,
+            };
+
+            for (conflict_pos, conflict_txid) in self.tx_conflicts_in_chain(full_tx) {
+                chain_conflicts.push((pos.clone(), txid, conflict_pos, conflict_txid))
+            }
+        }
+
+        for (update_pos, update_txid, conflicting_pos, conflicting_txid) in chain_conflicts {
+            // We have found a tx that conflicts with our update txid. Only allow this when the
+            // conflicting tx will be positioned as "unconfirmed" after the update is applied.
+            // If so, we will modify the changeset to evict the conflicting txid.
+
+            // determine the position of the conflicting txid after the current changeset is applied
+            let conflicting_new_pos = changeset
+                .chain
+                .txids
+                .get(&conflicting_txid)
+                .map(Option::as_ref)
+                .unwrap_or(Some(conflicting_pos));
+
+            match conflicting_new_pos {
+                None => {
+                    // conflicting txid will be deleted, can ignore
+                }
+                Some(existing_new_pos) => match existing_new_pos.height() {
+                    TxHeight::Confirmed(_) => {
+                        // the new position of the conflicting tx is "confirmed", therefore cannot be
+                        // evicted, return error
+                        return Err(UnresolvableConflict {
+                            already_confirmed_tx: (conflicting_pos.clone(), conflicting_txid),
+                            update_tx: (update_pos, update_txid),
+                        });
+                    }
+                    TxHeight::Unconfirmed => {
+                        // the new position of the conflicting tx is "unconfirmed", therefore it can
+                        // be evicted
+                        changeset.chain.txids.insert(conflicting_txid, None);
+                    }
+                },
+            };
+        }
+
+        Ok(())
+    }
+
+    /// Applies `changeset` to `self`.
+    ///
+    /// **Warning** this method assumes that the changeset is correctly formed. If it is not, the
+    /// chain graph may behave incorrectly in the future and panic unexpectedly.
+    pub fn apply_changeset(&mut self, changeset: ChangeSet<P>) {
+        self.chain.apply_changeset(changeset.chain);
+        self.graph.apply_additions(changeset.graph);
+    }
+
+    /// Applies the `update` chain graph. Note this is shorthand for calling
+    /// [`Self::determine_changeset()`] and [`Self::apply_changeset()`] in sequence.
+    pub fn apply_update(&mut self, update: ChainGraph<P>) -> Result<ChangeSet<P>, UpdateError<P>> {
+        let changeset = self.determine_changeset(&update)?;
+        self.apply_changeset(changeset.clone());
+        Ok(changeset)
+    }
+
+    /// Get the full transaction output at an outpoint if it exists in the chain and the graph.
+    pub fn full_txout(&self, outpoint: OutPoint) -> Option<FullTxOut<P>> {
+        self.chain.full_txout(&self.graph, outpoint)
+    }
+
+    /// Iterate over the full transactions and their position in the chain ordered by their position
+    /// in ascending order.
+    pub fn transactions_in_chain(&self) -> impl DoubleEndedIterator<Item = (&P, &Transaction)> {
+        self.chain
+            .txids()
+            .map(move |(pos, txid)| (pos, self.graph.get_tx(*txid).expect("must exist")))
+    }
+
+    /// Find the transaction in the chain that spends `outpoint`.
+    ///
+    /// This uses the input/output relationships in the internal `graph`. Note that the transaction
+    /// which includes `outpoint` does not need to be in the `graph` or the `chain` for this to
+    /// return `Some(_)`.
+    pub fn spent_by(&self, outpoint: OutPoint) -> Option<(&P, Txid)> {
+        self.chain.spent_by(&self.graph, outpoint)
+    }
+
+    /// Whether the chain graph contains any data whatsoever.
+    pub fn is_empty(&self) -> bool {
+        self.chain.is_empty() && self.graph.is_empty()
+    }
+}
+
+/// Represents changes to [`ChainGraph`].
+///
+/// This is essentially a combination of [`sparse_chain::ChangeSet`] and [`tx_graph::Additions`].
+#[derive(Debug, Clone, PartialEq)]
+#[cfg_attr(
+    feature = "serde",
+    derive(serde::Deserialize, serde::Serialize),
+    serde(
+        crate = "serde_crate",
+        bound(
+            deserialize = "P: serde::Deserialize<'de>",
+            serialize = "P: serde::Serialize"
+        )
+    )
+)]
+#[must_use]
+pub struct ChangeSet<P> {
+    pub chain: sparse_chain::ChangeSet<P>,
+    pub graph: tx_graph::Additions,
+}
+
+impl<P> ChangeSet<P> {
+    /// Returns `true` if this [`ChangeSet`] records no changes.
+    pub fn is_empty(&self) -> bool {
+        self.chain.is_empty() && self.graph.is_empty()
+    }
+
+    /// Returns `true` if this [`ChangeSet`] contains transaction evictions.
+    pub fn contains_eviction(&self) -> bool {
+        self.chain
+            .txids
+            .iter()
+            .any(|(_, new_pos)| new_pos.is_none())
+    }
+
+    /// Appends the changes in `other` into self such that applying `self` afterward has the same
+    /// effect as sequentially applying the original `self` and `other`.
+    pub fn append(&mut self, other: ChangeSet<P>)
+    where
+        P: ChainPosition,
+    {
+        self.chain.append(other.chain);
+        self.graph.append(other.graph);
+    }
+}
+
+impl<P> Default for ChangeSet<P> {
+    fn default() -> Self {
+        Self {
+            chain: Default::default(),
+            graph: Default::default(),
+        }
+    }
+}
+
+impl<P> ForEachTxOut for ChainGraph<P> {
+    fn for_each_txout(&self, f: impl FnMut((OutPoint, &TxOut))) {
+        self.graph.for_each_txout(f)
+    }
+}
+
+impl<P> ForEachTxOut for ChangeSet<P> {
+    fn for_each_txout(&self, f: impl FnMut((OutPoint, &TxOut))) {
+        self.graph.for_each_txout(f)
+    }
+}
+
+/// Error that may occur when calling [`ChainGraph::new`].
+#[derive(Clone, Debug, PartialEq)]
+pub enum NewError<P> {
+    /// Two transactions within the sparse chain conflicted with each other
+    Conflict { a: (P, Txid), b: (P, Txid) },
+    /// One or more transactions in the chain were not in the graph
+    Missing(HashSet<Txid>),
+}
+
+impl<P: core::fmt::Debug> core::fmt::Display for NewError<P> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self {
+            NewError::Conflict { a, b } => write!(
+                f,
+                "Unable to inflate sparse chain to chain graph since transactions {:?} and {:?}",
+                a, b
+            ),
+            NewError::Missing(missing) => write!(
+                f,
+                "missing full transactions for {}",
+                missing
+                    .iter()
+                    .map(|txid| txid.to_string())
+                    .collect::<Vec<_>>()
+                    .join(", ")
+            ),
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl<P: core::fmt::Debug> std::error::Error for NewError<P> {}
+
+/// Error that may occur when inserting a transaction.
+///
+/// Refer to [`ChainGraph::insert_tx_preview`] and [`ChainGraph::insert_tx`].
+#[derive(Clone, Debug, PartialEq)]
+pub enum InsertTxError<P> {
+    Chain(sparse_chain::InsertTxError<P>),
+    UnresolvableConflict(UnresolvableConflict<P>),
+}
+
+impl<P: core::fmt::Debug> core::fmt::Display for InsertTxError<P> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self {
+            InsertTxError::Chain(inner) => core::fmt::Display::fmt(inner, f),
+            InsertTxError::UnresolvableConflict(inner) => core::fmt::Display::fmt(inner, f),
+        }
+    }
+}
+
+impl<P> From<sparse_chain::InsertTxError<P>> for InsertTxError<P> {
+    fn from(inner: sparse_chain::InsertTxError<P>) -> Self {
+        Self::Chain(inner)
+    }
+}
+
+#[cfg(feature = "std")]
+impl<P: core::fmt::Debug> std::error::Error for InsertTxError<P> {}
+
+/// A nice alias of [`sparse_chain::InsertCheckpointError`].
+pub type InsertCheckpointError = sparse_chain::InsertCheckpointError;
+
+/// Represents an update failure.
+#[derive(Clone, Debug, PartialEq)]
+pub enum UpdateError<P> {
+    /// The update chain was inconsistent with the existing chain
+    Chain(sparse_chain::UpdateError<P>),
+    /// A transaction in the update spent the same input as an already confirmed transaction
+    UnresolvableConflict(UnresolvableConflict<P>),
+}
+
+impl<P: core::fmt::Debug> core::fmt::Display for UpdateError<P> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self {
+            UpdateError::Chain(inner) => core::fmt::Display::fmt(inner, f),
+            UpdateError::UnresolvableConflict(inner) => core::fmt::Display::fmt(inner, f),
+        }
+    }
+}
+
+impl<P> From<sparse_chain::UpdateError<P>> for UpdateError<P> {
+    fn from(inner: sparse_chain::UpdateError<P>) -> Self {
+        Self::Chain(inner)
+    }
+}
+
+#[cfg(feature = "std")]
+impl<P: core::fmt::Debug> std::error::Error for UpdateError<P> {}
+
+/// Represents an unresolvable conflict between an update's transaction and an
+/// already-confirmed transaction.
+#[derive(Clone, Debug, PartialEq)]
+pub struct UnresolvableConflict<P> {
+    pub already_confirmed_tx: (P, Txid),
+    pub update_tx: (P, Txid),
+}
+
+impl<P: core::fmt::Debug> core::fmt::Display for UnresolvableConflict<P> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        let Self {
+            already_confirmed_tx,
+            update_tx,
+        } = self;
+        write!(f, "update transaction {} at height {:?} conflicts with an already confirmed transaction {} at height {:?}",
+            update_tx.1, update_tx.0, already_confirmed_tx.1, already_confirmed_tx.0)
+    }
+}
+
+impl<P> From<UnresolvableConflict<P>> for UpdateError<P> {
+    fn from(inner: UnresolvableConflict<P>) -> Self {
+        Self::UnresolvableConflict(inner)
+    }
+}
+
+impl<P> From<UnresolvableConflict<P>> for InsertTxError<P> {
+    fn from(inner: UnresolvableConflict<P>) -> Self {
+        Self::UnresolvableConflict(inner)
+    }
+}
+
+#[cfg(feature = "std")]
+impl<P: core::fmt::Debug> std::error::Error for UnresolvableConflict<P> {}
--- a/crates/chain/src/chain_oracle.rs
+++ b/crates/chain/src/chain_oracle.rs
@@ -1,25 +0,0 @@
-use crate::BlockId;
-
-/// Represents a service that tracks the blockchain.
-///
-/// The main method is [`is_block_in_chain`] which determines whether a given block of [`BlockId`]
-/// is an ancestor of another "static block".
-///
-/// [`is_block_in_chain`]: Self::is_block_in_chain
-pub trait ChainOracle {
-    /// Error type.
-    type Error: core::fmt::Debug;
-
-    /// Determines whether `block` of [`BlockId`] exists as an ancestor of `chain_tip`.
-    ///
-    /// If `None` is returned, it means the implementation cannot determine whether `block` exists
-    /// under `chain_tip`.
-    fn is_block_in_chain(
-        &self,
-        block: BlockId,
-        chain_tip: BlockId,
-    ) -> Result<Option<bool>, Self::Error>;
-
-    /// Get the best chain's chain tip.
-    fn get_chain_tip(&self) -> Result<Option<BlockId>, Self::Error>;
-}
--- a/crates/chain/src/indexed_tx_graph.rs
+++ b/crates/chain/src/indexed_tx_graph.rs
@@ -1,245 +0,0 @@
-//! Contains the [`IndexedTxGraph`] structure and associated types.
-//!
-//! This is essentially a [`TxGraph`] combined with an indexer.
-
-use alloc::vec::Vec;
-use bitcoin::{OutPoint, Transaction, TxOut};
-
-use crate::{
-    keychain::DerivationAdditions,
-    tx_graph::{Additions, TxGraph},
-    Anchor, Append,
-};
-
-/// A struct that combines [`TxGraph`] and an [`Indexer`] implementation.
-///
-/// This structure ensures that [`TxGraph`] and [`Indexer`] are updated atomically.
-#[derive(Debug)]
-pub struct IndexedTxGraph<A, I> {
-    /// Transaction index.
-    pub index: I,
-    graph: TxGraph<A>,
-}
-
-impl<A, I: Default> Default for IndexedTxGraph<A, I> {
-    fn default() -> Self {
-        Self {
-            graph: Default::default(),
-            index: Default::default(),
-        }
-    }
-}
-
-impl<A, I> IndexedTxGraph<A, I> {
-    /// Construct a new [`IndexedTxGraph`] with a given `index`.
-    pub fn new(index: I) -> Self {
-        Self {
-            index,
-            graph: TxGraph::default(),
-        }
-    }
-
-    /// Get a reference of the internal transaction graph.
-    pub fn graph(&self) -> &TxGraph<A> {
-        &self.graph
-    }
-}
-
-impl<A: Anchor, I: Indexer> IndexedTxGraph<A, I> {
-    /// Applies the [`IndexedAdditions`] to the [`IndexedTxGraph`].
-    pub fn apply_additions(&mut self, additions: IndexedAdditions<A, I::Additions>) {
-        let IndexedAdditions {
-            graph_additions,
-            index_additions,
-        } = additions;
-
-        self.index.apply_additions(index_additions);
-
-        for tx in &graph_additions.txs {
-            self.index.index_tx(tx);
-        }
-        for (&outpoint, txout) in &graph_additions.txouts {
-            self.index.index_txout(outpoint, txout);
-        }
-
-        self.graph.apply_additions(graph_additions);
-    }
-}
-
-impl<A: Anchor, I: Indexer> IndexedTxGraph<A, I>
-where
-    I::Additions: Default + Append,
-{
-    /// Apply an `update` directly.
-    ///
-    /// `update` is a [`TxGraph<A>`] and the resultant changes is returned as [`IndexedAdditions`].
-    pub fn apply_update(&mut self, update: TxGraph<A>) -> IndexedAdditions<A, I::Additions> {
-        let graph_additions = self.graph.apply_update(update);
-
-        let mut index_additions = I::Additions::default();
-        for added_tx in &graph_additions.txs {
-            index_additions.append(self.index.index_tx(added_tx));
-        }
-        for (&added_outpoint, added_txout) in &graph_additions.txouts {
-            index_additions.append(self.index.index_txout(added_outpoint, added_txout));
-        }
-
-        IndexedAdditions {
-            graph_additions,
-            index_additions,
-        }
-    }
-
-    /// Insert a floating `txout` of given `outpoint`.
-    pub fn insert_txout(
-        &mut self,
-        outpoint: OutPoint,
-        txout: &TxOut,
-    ) -> IndexedAdditions<A, I::Additions> {
-        let mut update = TxGraph::<A>::default();
-        let _ = update.insert_txout(outpoint, txout.clone());
-        self.apply_update(update)
-    }
-
-    /// Insert and index a transaction into the graph.
-    ///
-    /// `anchors` can be provided to anchor the transaction to various blocks. `seen_at` is a
-    /// unix timestamp of when the transaction is last seen.
-    pub fn insert_tx(
-        &mut self,
-        tx: &Transaction,
-        anchors: impl IntoIterator<Item = A>,
-        seen_at: Option<u64>,
-    ) -> IndexedAdditions<A, I::Additions> {
-        let txid = tx.txid();
-
-        let mut update = TxGraph::<A>::default();
-        if self.graph.get_tx(txid).is_none() {
-            let _ = update.insert_tx(tx.clone());
-        }
-        for anchor in anchors.into_iter() {
-            let _ = update.insert_anchor(txid, anchor);
-        }
-        if let Some(seen_at) = seen_at {
-            let _ = update.insert_seen_at(txid, seen_at);
-        }
-
-        self.apply_update(update)
-    }
-
-    /// Insert relevant transactions from the given `txs` iterator.
-    ///
-    /// Relevancy is determined by the [`Indexer::is_tx_relevant`] implementation of `I`. Irrelevant
-    /// transactions in `txs` will be ignored. `txs` do not need to be in topological order.
-    ///
-    /// `anchors` can be provided to anchor the transactions to blocks. `seen_at` is a unix
-    /// timestamp of when the transactions are last seen.
-    pub fn insert_relevant_txs<'t>(
-        &mut self,
-        txs: impl IntoIterator<Item = (&'t Transaction, impl IntoIterator<Item = A>)>,
-        seen_at: Option<u64>,
-    ) -> IndexedAdditions<A, I::Additions> {
-        // The algorithm below allows for non-topologically ordered transactions by using two loops.
-        // This is achieved by:
-        // 1. insert all txs into the index. If they are irrelevant then that's fine it will just
-        //    not store anything about them.
-        // 2. decide whether to insert them into the graph depending on whether `is_tx_relevant`
-        //    returns true or not. (in a second loop).
-        let mut additions = IndexedAdditions::<A, I::Additions>::default();
-        let mut transactions = Vec::new();
-        for (tx, anchors) in txs.into_iter() {
-            additions.index_additions.append(self.index.index_tx(tx));
-            transactions.push((tx, anchors));
-        }
-        additions.append(
-            transactions
-                .into_iter()
-                .filter_map(|(tx, anchors)| match self.index.is_tx_relevant(tx) {
-                    true => Some(self.insert_tx(tx, anchors, seen_at)),
-                    false => None,
-                })
-                .fold(Default::default(), |mut acc, other| {
-                    acc.append(other);
-                    acc
-                }),
-        );
-        additions
-    }
-}
-
-/// A structure that represents changes to an [`IndexedTxGraph`].
-#[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(
-    feature = "serde",
-    derive(serde::Deserialize, serde::Serialize),
-    serde(
-        crate = "serde_crate",
-        bound(
-            deserialize = "A: Ord + serde::Deserialize<'de>, IA: serde::Deserialize<'de>",
-            serialize = "A: Ord + serde::Serialize, IA: serde::Serialize"
-        )
-    )
-)]
-#[must_use]
-pub struct IndexedAdditions<A, IA> {
-    /// [`TxGraph`] additions.
-    pub graph_additions: Additions<A>,
-    /// [`Indexer`] additions.
-    pub index_additions: IA,
-}
-
-impl<A, IA: Default> Default for IndexedAdditions<A, IA> {
-    fn default() -> Self {
-        Self {
-            graph_additions: Default::default(),
-            index_additions: Default::default(),
-        }
-    }
-}
-
-impl<A: Anchor, IA: Append> Append for IndexedAdditions<A, IA> {
-    fn append(&mut self, other: Self) {
-        self.graph_additions.append(other.graph_additions);
-        self.index_additions.append(other.index_additions);
-    }
-
-    fn is_empty(&self) -> bool {
-        self.graph_additions.is_empty() && self.index_additions.is_empty()
-    }
-}
-
-impl<A, IA: Default> From<Additions<A>> for IndexedAdditions<A, IA> {
-    fn from(graph_additions: Additions<A>) -> Self {
-        Self {
-            graph_additions,
-            ..Default::default()
-        }
-    }
-}
-
-impl<A, K> From<DerivationAdditions<K>> for IndexedAdditions<A, DerivationAdditions<K>> {
-    fn from(index_additions: DerivationAdditions<K>) -> Self {
-        Self {
-            graph_additions: Default::default(),
-            index_additions,
-        }
-    }
-}
-
-/// Represents a structure that can index transaction data.
-pub trait Indexer {
-    /// The resultant "additions" when new transaction data is indexed.
-    type Additions;
-
-    /// Scan and index the given `outpoint` and `txout`.
-    fn index_txout(&mut self, outpoint: OutPoint, txout: &TxOut) -> Self::Additions;
-
-    /// Scan and index the given transaction.
-    fn index_tx(&mut self, tx: &Transaction) -> Self::Additions;
-
-    /// Apply additions to itself.
-    fn apply_additions(&mut self, additions: Self::Additions);
-
-    /// Determines whether the transaction should be included in the index.
-    fn is_tx_relevant(&self, tx: &Transaction) -> bool;
-}
--- a/crates/chain/src/keychain.rs
+++ b/crates/chain/src/keychain.rs
@@ -8,16 +8,28 @@
 //! has a `txout` containing an indexed script pubkey). Internally, this uses [`SpkTxOutIndex`], but
 //! also maintains "revealed" and "lookahead" index counts per keychain.
 //!
+//! [`KeychainTracker`] combines [`ChainGraph`] and [`KeychainTxOutIndex`] and enforces atomic
+//! changes between both these structures. [`KeychainScan`] is a structure used to update to
+//! [`KeychainTracker`] and changes made on a [`KeychainTracker`] are reported by
+//! [`KeychainChangeSet`]s.
+//!
 //! [`SpkTxOutIndex`]: crate::SpkTxOutIndex
-
 use crate::{
+    chain_graph::{self, ChainGraph},
    collections::BTreeMap,
-    indexed_tx_graph::IndexedAdditions,
-    local_chain::{self, LocalChain},
+    sparse_chain::ChainPosition,
    tx_graph::TxGraph,
-    Anchor, Append,
+    ForEachTxOut,
 };

+#[cfg(feature = "miniscript")]
+pub mod persist;
+#[cfg(feature = "miniscript")]
+pub use persist::*;
+#[cfg(feature = "miniscript")]
+mod tracker;
+#[cfg(feature = "miniscript")]
+pub use tracker::*;
 #[cfg(feature = "miniscript")]
 mod txout_index;
 #[cfg(feature = "miniscript")]
@@ -57,12 +69,12 @@ impl<K> DerivationAdditions<K> {
    }
 }

-impl<K: Ord> Append for DerivationAdditions<K> {
+impl<K: Ord> DerivationAdditions<K> {
    /// Append another [`DerivationAdditions`] into self.
    ///
    /// If the keychain already exists, increase the index when the other's index > self's index.
    /// If the keychain did not exist, append the new keychain.
-    fn append(&mut self, mut other: Self) {
+    pub fn append(&mut self, mut other: Self) {
        self.0.iter_mut().for_each(|(key, index)| {
            if let Some(other_index) = other.0.remove(key) {
                *index = other_index.max(*index);
@@ -71,10 +83,6 @@ impl<K: Ord> Append for DerivationAdditions<K> {

        self.0.append(&mut other.0);
    }
-
-    fn is_empty(&self) -> bool {
-        self.0.is_empty()
-    }
 }

 impl<K> Default for DerivationAdditions<K> {
@@ -89,89 +97,116 @@ impl<K> AsRef<BTreeMap<K, u32>> for DerivationAdditions<K> {
    }
 }

-/// A structure to update [`KeychainTxOutIndex`], [`TxGraph`] and [`LocalChain`]
-/// atomically.
-#[derive(Debug, Clone, PartialEq)]
-pub struct LocalUpdate<K, A> {
-    /// Last active derivation index per keychain (`K`).
-    pub keychain: BTreeMap<K, u32>,
-    /// Update for the [`TxGraph`].
-    pub graph: TxGraph<A>,
-    /// Update for the [`LocalChain`].
-    pub chain: LocalChain,
+#[derive(Clone, Debug, PartialEq)]
+/// An update that includes the last active indexes of each keychain.
+pub struct KeychainScan<K, P> {
+    /// The update data in the form of a chain that could be applied
+    pub update: ChainGraph<P>,
+    /// The last active indexes of each keychain
+    pub last_active_indices: BTreeMap<K, u32>,
 }

-impl<K, A> Default for LocalUpdate<K, A> {
+impl<K, P> Default for KeychainScan<K, P> {
    fn default() -> Self {
        Self {
-            keychain: Default::default(),
-            graph: Default::default(),
-            chain: Default::default(),
+            update: Default::default(),
+            last_active_indices: Default::default(),
        }
    }
 }

-/// A structure that records the corresponding changes as result of applying an [`LocalUpdate`].
-#[derive(Debug, Clone, PartialEq)]
+impl<K, P> From<ChainGraph<P>> for KeychainScan<K, P> {
+    fn from(update: ChainGraph<P>) -> Self {
+        KeychainScan {
+            update,
+            last_active_indices: Default::default(),
+        }
+    }
+}
+
+/// Represents changes to a [`KeychainTracker`].
+///
+/// This is essentially a combination of [`DerivationAdditions`] and [`chain_graph::ChangeSet`].
+#[derive(Clone, Debug)]
 #[cfg_attr(
    feature = "serde",
    derive(serde::Deserialize, serde::Serialize),
    serde(
        crate = "serde_crate",
        bound(
-            deserialize = "K: Ord + serde::Deserialize<'de>, A: Ord + serde::Deserialize<'de>",
-            serialize = "K: Ord + serde::Serialize, A: Ord + serde::Serialize",
+            deserialize = "K: Ord + serde::Deserialize<'de>, P: serde::Deserialize<'de>",
+            serialize = "K: Ord + serde::Serialize, P: serde::Serialize"
        )
    )
 )]
-pub struct LocalChangeSet<K, A> {
-    /// Changes to the [`LocalChain`].
-    pub chain_changeset: local_chain::ChangeSet,
-
-    /// Additions to [`IndexedTxGraph`].
-    ///
-    /// [`IndexedTxGraph`]: crate::indexed_tx_graph::IndexedTxGraph
-    pub indexed_additions: IndexedAdditions<A, DerivationAdditions<K>>,
+#[must_use]
+pub struct KeychainChangeSet<K, P> {
+    /// The changes in local keychain derivation indices
+    pub derivation_indices: DerivationAdditions<K>,
+    /// The changes that have occurred in the blockchain
+    pub chain_graph: chain_graph::ChangeSet<P>,
 }

-impl<K, A> Default for LocalChangeSet<K, A> {
+impl<K, P> Default for KeychainChangeSet<K, P> {
    fn default() -> Self {
        Self {
-            chain_changeset: Default::default(),
-            indexed_additions: Default::default(),
+            chain_graph: Default::default(),
+            derivation_indices: Default::default(),
        }
    }
 }

-impl<K: Ord, A: Anchor> Append for LocalChangeSet<K, A> {
-    fn append(&mut self, other: Self) {
-        Append::append(&mut self.chain_changeset, other.chain_changeset);
-        Append::append(&mut self.indexed_additions, other.indexed_additions);
+impl<K, P> KeychainChangeSet<K, P> {
+    /// Returns whether the [`KeychainChangeSet`] is empty (no changes recorded).
+    pub fn is_empty(&self) -> bool {
+        self.chain_graph.is_empty() && self.derivation_indices.is_empty()
    }

-    fn is_empty(&self) -> bool {
-        self.chain_changeset.is_empty() && self.indexed_additions.is_empty()
+    /// Appends the changes in `other` into `self` such that applying `self` afterward has the same
+    /// effect as sequentially applying the original `self` and `other`.
+    ///
+    /// Note the derivation indices cannot be decreased, so `other` will only change the derivation
+    /// index for a keychain, if it's value is higher than the one in `self`.
+    pub fn append(&mut self, other: KeychainChangeSet<K, P>)
+    where
+        K: Ord,
+        P: ChainPosition,
+    {
+        self.derivation_indices.append(other.derivation_indices);
+        self.chain_graph.append(other.chain_graph);
    }
 }

-impl<K, A> From<local_chain::ChangeSet> for LocalChangeSet<K, A> {
-    fn from(chain_changeset: local_chain::ChangeSet) -> Self {
+impl<K, P> From<chain_graph::ChangeSet<P>> for KeychainChangeSet<K, P> {
+    fn from(changeset: chain_graph::ChangeSet<P>) -> Self {
        Self {
-            chain_changeset,
+            chain_graph: changeset,
            ..Default::default()
        }
    }
 }

-impl<K, A> From<IndexedAdditions<A, DerivationAdditions<K>>> for LocalChangeSet<K, A> {
-    fn from(indexed_additions: IndexedAdditions<A, DerivationAdditions<K>>) -> Self {
+impl<K, P> From<DerivationAdditions<K>> for KeychainChangeSet<K, P> {
+    fn from(additions: DerivationAdditions<K>) -> Self {
        Self {
-            indexed_additions,
+            derivation_indices: additions,
            ..Default::default()
        }
    }
 }

+impl<K, P> AsRef<TxGraph> for KeychainScan<K, P> {
+    fn as_ref(&self) -> &TxGraph {
+        self.update.graph()
+    }
+}
+
+impl<K, P> ForEachTxOut for KeychainChangeSet<K, P> {
+    fn for_each_txout(&self, f: impl FnMut((bitcoin::OutPoint, &bitcoin::TxOut))) {
+        self.chain_graph.for_each_txout(f)
+    }
+}
+
 /// Balance, differentiated into various categories.
 #[derive(Debug, PartialEq, Eq, Clone, Default)]
 #[cfg_attr(
@@ -230,8 +265,9 @@ impl core::ops::Add for Balance {

 #[cfg(test)]
 mod test {
-    use super::*;
+    use crate::TxHeight;

+    use super::*;
    #[test]
    fn append_keychain_derivation_indices() {
        #[derive(Ord, PartialOrd, Eq, PartialEq, Clone, Debug)]
@@ -249,18 +285,25 @@ mod test {
        rhs_di.insert(Keychain::Two, 5);
        lhs_di.insert(Keychain::Three, 3);
        rhs_di.insert(Keychain::Four, 4);
+        let mut lhs = KeychainChangeSet {
+            derivation_indices: DerivationAdditions(lhs_di),
+            chain_graph: chain_graph::ChangeSet::<TxHeight>::default(),
+        };
+
+        let rhs = KeychainChangeSet {
+            derivation_indices: DerivationAdditions(rhs_di),
+            chain_graph: chain_graph::ChangeSet::<TxHeight>::default(),
+        };

-        let mut lhs = DerivationAdditions(lhs_di);
-        let rhs = DerivationAdditions(rhs_di);
        lhs.append(rhs);

        // Exiting index doesn't update if the new index in `other` is lower than `self`.
-        assert_eq!(lhs.0.get(&Keychain::One), Some(&7));
+        assert_eq!(lhs.derivation_indices.0.get(&Keychain::One), Some(&7));
        // Existing index updates if the new index in `other` is higher than `self`.
-        assert_eq!(lhs.0.get(&Keychain::Two), Some(&5));
+        assert_eq!(lhs.derivation_indices.0.get(&Keychain::Two), Some(&5));
        // Existing index is unchanged if keychain doesn't exist in `other`.
-        assert_eq!(lhs.0.get(&Keychain::Three), Some(&3));
+        assert_eq!(lhs.derivation_indices.0.get(&Keychain::Three), Some(&3));
        // New keychain gets added if the keychain is in `other` but not in `self`.
-        assert_eq!(lhs.0.get(&Keychain::Four), Some(&4));
+        assert_eq!(lhs.derivation_indices.0.get(&Keychain::Four), Some(&4));
    }
 }
--- a/crates/chain/src/keychain/persist.rs
+++ b/crates/chain/src/keychain/persist.rs
@@ -0,0 +1,108 @@
+//! Persistence for changes made to a [`KeychainTracker`].
+//!
+//! BDK's [`KeychainTracker`] needs somewhere to persist changes it makes during operation.
+//! Operations like giving out a new address are crucial to persist so that next time the
+//! application is loaded, it can find transactions related to that address.
+//!
+//! Note that the [`KeychainTracker`] does not read this persisted data during operation since it
+//! always has a copy in memory.
+//!
+//! [`KeychainTracker`]: crate::keychain::KeychainTracker
+
+use crate::{keychain, sparse_chain::ChainPosition};
+
+/// `Persist` wraps a [`PersistBackend`] to create a convenient staging area for changes before they
+/// are persisted. Not all changes made to the [`KeychainTracker`] need to be written to disk right
+/// away so you can use [`Persist::stage`] to *stage* it first and then [`Persist::commit`] to
+/// finally, write it to disk.
+///
+/// [`KeychainTracker`]: keychain::KeychainTracker
+#[derive(Debug)]
+pub struct Persist<K, P, B> {
+    backend: B,
+    stage: keychain::KeychainChangeSet<K, P>,
+}
+
+impl<K, P, B> Persist<K, P, B> {
+    /// Create a new `Persist` from a [`PersistBackend`].
+    pub fn new(backend: B) -> Self {
+        Self {
+            backend,
+            stage: Default::default(),
+        }
+    }
+
+    /// Stage a `changeset` to later persistence with [`commit`].
+    ///
+    /// [`commit`]: Self::commit
+    pub fn stage(&mut self, changeset: keychain::KeychainChangeSet<K, P>)
+    where
+        K: Ord,
+        P: ChainPosition,
+    {
+        self.stage.append(changeset)
+    }
+
+    /// Get the changes that haven't been committed yet
+    pub fn staged(&self) -> &keychain::KeychainChangeSet<K, P> {
+        &self.stage
+    }
+
+    /// Commit the staged changes to the underlying persistence backend.
+    ///
+    /// Returns a backend-defined error if this fails.
+    pub fn commit(&mut self) -> Result<(), B::WriteError>
+    where
+        B: PersistBackend<K, P>,
+    {
+        self.backend.append_changeset(&self.stage)?;
+        self.stage = Default::default();
+        Ok(())
+    }
+}
+
+/// A persistence backend for [`Persist`].
+pub trait PersistBackend<K, P> {
+    /// The error the backend returns when it fails to write.
+    type WriteError: core::fmt::Debug;
+
+    /// The error the backend returns when it fails to load.
+    type LoadError: core::fmt::Debug;
+
+    /// Appends a new changeset to the persistent backend.
+    ///
+    /// It is up to the backend what it does with this. It could store every changeset in a list or
+    /// it inserts the actual changes into a more structured database. All it needs to guarantee is
+    /// that [`load_into_keychain_tracker`] restores a keychain tracker to what it should be if all
+    /// changesets had been applied sequentially.
+    ///
+    /// [`load_into_keychain_tracker`]: Self::load_into_keychain_tracker
+    fn append_changeset(
+        &mut self,
+        changeset: &keychain::KeychainChangeSet<K, P>,
+    ) -> Result<(), Self::WriteError>;
+
+    /// Applies all the changesets the backend has received to `tracker`.
+    fn load_into_keychain_tracker(
+        &mut self,
+        tracker: &mut keychain::KeychainTracker<K, P>,
+    ) -> Result<(), Self::LoadError>;
+}
+
+impl<K, P> PersistBackend<K, P> for () {
+    type WriteError = ();
+    type LoadError = ();
+
+    fn append_changeset(
+        &mut self,
+        _changeset: &keychain::KeychainChangeSet<K, P>,
+    ) -> Result<(), Self::WriteError> {
+        Ok(())
+    }
+    fn load_into_keychain_tracker(
+        &mut self,
+        _tracker: &mut keychain::KeychainTracker<K, P>,
+    ) -> Result<(), Self::LoadError> {
+        Ok(())
+    }
+}
--- a/crates/chain/src/keychain/tracker.rs
+++ b/crates/chain/src/keychain/tracker.rs
@@ -0,0 +1,308 @@
+use bitcoin::Transaction;
+use miniscript::{Descriptor, DescriptorPublicKey};
+
+use crate::{
+    chain_graph::{self, ChainGraph},
+    collections::*,
+    keychain::{KeychainChangeSet, KeychainScan, KeychainTxOutIndex},
+    sparse_chain::{self, SparseChain},
+    tx_graph::TxGraph,
+    BlockId, FullTxOut, TxHeight,
+};
+
+use super::{Balance, DerivationAdditions};
+
+/// A convenient combination of a [`KeychainTxOutIndex`] and a [`ChainGraph`].
+///
+/// The [`KeychainTracker`] atomically updates its [`KeychainTxOutIndex`] whenever new chain data is
+/// incorporated into its internal [`ChainGraph`].
+#[derive(Clone, Debug)]
+pub struct KeychainTracker<K, P> {
+    /// Index between script pubkeys to transaction outputs
+    pub txout_index: KeychainTxOutIndex<K>,
+    chain_graph: ChainGraph<P>,
+}
+
+impl<K, P> KeychainTracker<K, P>
+where
+    P: sparse_chain::ChainPosition,
+    K: Ord + Clone + core::fmt::Debug,
+{
+    /// Add a keychain to the tracker's `txout_index` with a descriptor to derive addresses.
+    /// This is just shorthand for calling [`KeychainTxOutIndex::add_keychain`] on the internal
+    /// `txout_index`.
+    ///
+    /// Adding a keychain means you will be able to derive new script pubkeys under that keychain
+    /// and the tracker will discover transaction outputs with those script pubkeys.
+    pub fn add_keychain(&mut self, keychain: K, descriptor: Descriptor<DescriptorPublicKey>) {
+        self.txout_index.add_keychain(keychain, descriptor)
+    }
+
+    /// Get the internal map of keychains to their descriptors. This is just shorthand for calling
+    /// [`KeychainTxOutIndex::keychains`] on the internal `txout_index`.
+    pub fn keychains(&mut self) -> &BTreeMap<K, Descriptor<DescriptorPublicKey>> {
+        self.txout_index.keychains()
+    }
+
+    /// Get the checkpoint limit of the internal [`SparseChain`].
+    ///
+    /// Refer to [`SparseChain::checkpoint_limit`] for more.
+    pub fn checkpoint_limit(&self) -> Option<usize> {
+        self.chain_graph.checkpoint_limit()
+    }
+
+    /// Set the checkpoint limit of the internal [`SparseChain`].
+    ///
+    /// Refer to [`SparseChain::set_checkpoint_limit`] for more.
+    pub fn set_checkpoint_limit(&mut self, limit: Option<usize>) {
+        self.chain_graph.set_checkpoint_limit(limit)
+    }
+
+    /// Determines the resultant [`KeychainChangeSet`] if the given [`KeychainScan`] is applied.
+    ///
+    /// Internally, we call [`ChainGraph::determine_changeset`] and also determine the additions of
+    /// [`KeychainTxOutIndex`].
+    pub fn determine_changeset(
+        &self,
+        scan: &KeychainScan<K, P>,
+    ) -> Result<KeychainChangeSet<K, P>, chain_graph::UpdateError<P>> {
+        // TODO: `KeychainTxOutIndex::determine_additions`
+        let mut derivation_indices = scan.last_active_indices.clone();
+        derivation_indices.retain(|keychain, index| {
+            match self.txout_index.last_revealed_index(keychain) {
+                Some(existing) => *index > existing,
+                None => true,
+            }
+        });
+
+        Ok(KeychainChangeSet {
+            derivation_indices: DerivationAdditions(derivation_indices),
+            chain_graph: self.chain_graph.determine_changeset(&scan.update)?,
+        })
+    }
+
+    /// Directly applies a [`KeychainScan`] on [`KeychainTracker`].
+    ///
+    /// This is equivalent to calling [`determine_changeset`] and [`apply_changeset`] in sequence.
+    ///
+    /// [`determine_changeset`]: Self::determine_changeset
+    /// [`apply_changeset`]: Self::apply_changeset
+    pub fn apply_update(
+        &mut self,
+        scan: KeychainScan<K, P>,
+    ) -> Result<KeychainChangeSet<K, P>, chain_graph::UpdateError<P>> {
+        let changeset = self.determine_changeset(&scan)?;
+        self.apply_changeset(changeset.clone());
+        Ok(changeset)
+    }
+
+    /// Applies the changes in `changeset` to [`KeychainTracker`].
+    ///
+    /// Internally, this calls [`KeychainTxOutIndex::apply_additions`] and
+    /// [`ChainGraph::apply_changeset`] in sequence.
+    pub fn apply_changeset(&mut self, changeset: KeychainChangeSet<K, P>) {
+        let KeychainChangeSet {
+            derivation_indices,
+            chain_graph,
+        } = changeset;
+        self.txout_index.apply_additions(derivation_indices);
+        let _ = self.txout_index.scan(&chain_graph);
+        self.chain_graph.apply_changeset(chain_graph)
+    }
+
+    /// Iterates through [`FullTxOut`]s that are considered to exist in our representation of the
+    /// blockchain/mempool.
+    ///
+    /// In other words, these are `txout`s of confirmed and in-mempool transactions, based on our
+    /// view of the blockchain/mempool.
+    pub fn full_txouts(&self) -> impl Iterator<Item = (&(K, u32), FullTxOut<P>)> + '_ {
+        self.txout_index
+            .txouts()
+            .filter_map(move |(spk_i, op, _)| Some((spk_i, self.chain_graph.full_txout(op)?)))
+    }
+
+    /// Iterates through [`FullTxOut`]s that are unspent outputs.
+    ///
+    /// Refer to [`full_txouts`] for more.
+    ///
+    /// [`full_txouts`]: Self::full_txouts
+    pub fn full_utxos(&self) -> impl Iterator<Item = (&(K, u32), FullTxOut<P>)> + '_ {
+        self.full_txouts()
+            .filter(|(_, txout)| txout.spent_by.is_none())
+    }
+
+    /// Returns a reference to the internal [`ChainGraph`].
+    pub fn chain_graph(&self) -> &ChainGraph<P> {
+        &self.chain_graph
+    }
+
+    /// Returns a reference to the internal [`TxGraph`] (which is part of the [`ChainGraph`]).
+    pub fn graph(&self) -> &TxGraph {
+        self.chain_graph().graph()
+    }
+
+    /// Returns a reference to the internal [`SparseChain`] (which is part of the [`ChainGraph`]).
+    pub fn chain(&self) -> &SparseChain<P> {
+        self.chain_graph().chain()
+    }
+
+    /// Determines the changes as a result of inserting `block_id` (a height and block hash) into the
+    /// tracker.
+    ///
+    /// The caller is responsible for guaranteeing that a block exists at that height. If a
+    /// checkpoint already exists at that height with a different hash; this will return an error.
+    /// Otherwise it will return `Ok(true)` if the checkpoint didn't already exist or `Ok(false)`
+    /// if it did.
+    ///
+    /// **Warning**: This function modifies the internal state of the tracker. You are responsible
+    /// for persisting these changes to disk if you need to restore them.
+    pub fn insert_checkpoint_preview(
+        &self,
+        block_id: BlockId,
+    ) -> Result<KeychainChangeSet<K, P>, chain_graph::InsertCheckpointError> {
+        Ok(KeychainChangeSet {
+            chain_graph: self.chain_graph.insert_checkpoint_preview(block_id)?,
+            ..Default::default()
+        })
+    }
+
+    /// Directly insert a `block_id` into the tracker.
+    ///
+    /// This is equivalent of calling [`insert_checkpoint_preview`] and [`apply_changeset`] in
+    /// sequence.
+    ///
+    /// [`insert_checkpoint_preview`]: Self::insert_checkpoint_preview
+    /// [`apply_changeset`]: Self::apply_changeset
+    pub fn insert_checkpoint(
+        &mut self,
+        block_id: BlockId,
+    ) -> Result<KeychainChangeSet<K, P>, chain_graph::InsertCheckpointError> {
+        let changeset = self.insert_checkpoint_preview(block_id)?;
+        self.apply_changeset(changeset.clone());
+        Ok(changeset)
+    }
+
+    /// Determines the changes as a result of inserting a transaction into the inner [`ChainGraph`]
+    /// and optionally into the inner chain at `position`.
+    ///
+    /// **Warning**: This function modifies the internal state of the chain graph. You are
+    /// responsible for persisting these changes to disk if you need to restore them.
+    pub fn insert_tx_preview(
+        &self,
+        tx: Transaction,
+        pos: P,
+    ) -> Result<KeychainChangeSet<K, P>, chain_graph::InsertTxError<P>> {
+        Ok(KeychainChangeSet {
+            chain_graph: self.chain_graph.insert_tx_preview(tx, pos)?,
+            ..Default::default()
+        })
+    }
+
+    /// Directly insert a transaction into the inner [`ChainGraph`] and optionally into the inner
+    /// chain at `position`.
+    ///
+    /// This is equivalent of calling [`insert_tx_preview`] and [`apply_changeset`] in sequence.
+    ///
+    /// [`insert_tx_preview`]: Self::insert_tx_preview
+    /// [`apply_changeset`]: Self::apply_changeset
+    pub fn insert_tx(
+        &mut self,
+        tx: Transaction,
+        pos: P,
+    ) -> Result<KeychainChangeSet<K, P>, chain_graph::InsertTxError<P>> {
+        let changeset = self.insert_tx_preview(tx, pos)?;
+        self.apply_changeset(changeset.clone());
+        Ok(changeset)
+    }
+
+    /// Returns the *balance* of the keychain, i.e., the value of unspent transaction outputs tracked.
+    ///
+    /// The caller provides a `should_trust` predicate which must decide whether the value of
+    /// unconfirmed outputs on this keychain are guaranteed to be realized or not. For example:
+    ///
+    /// - For an *internal* (change) keychain, `should_trust` should generally be `true` since even if
+    /// you lose an internal output due to eviction, you will always gain back the value from whatever output the
+    /// unconfirmed transaction was spending (since that output is presumably from your wallet).
+    /// - For an *external* keychain, you might want `should_trust` to return  `false` since someone may cancel (by double spending)
+    /// a payment made to addresses on that keychain.
+    ///
+    /// When in doubt set `should_trust` to return false. This doesn't do anything other than change
+    /// where the unconfirmed output's value is accounted for in `Balance`.
+    pub fn balance(&self, mut should_trust: impl FnMut(&K) -> bool) -> Balance {
+        let mut immature = 0;
+        let mut trusted_pending = 0;
+        let mut untrusted_pending = 0;
+        let mut confirmed = 0;
+        let last_sync_height = self.chain().latest_checkpoint().map(|latest| latest.height);
+        for ((keychain, _), utxo) in self.full_utxos() {
+            let chain_position = &utxo.chain_position;
+
+            match chain_position.height() {
+                TxHeight::Confirmed(_) => {
+                    if utxo.is_on_coinbase {
+                        if utxo.is_mature(
+                            last_sync_height
+                                .expect("since it's confirmed we must have a checkpoint"),
+                        ) {
+                            confirmed += utxo.txout.value;
+                        } else {
+                            immature += utxo.txout.value;
+                        }
+                    } else {
+                        confirmed += utxo.txout.value;
+                    }
+                }
+                TxHeight::Unconfirmed => {
+                    if should_trust(keychain) {
+                        trusted_pending += utxo.txout.value;
+                    } else {
+                        untrusted_pending += utxo.txout.value;
+                    }
+                }
+            }
+        }
+
+        Balance {
+            immature,
+            trusted_pending,
+            untrusted_pending,
+            confirmed,
+        }
+    }
+
+    /// Returns the balance of all spendable confirmed unspent outputs of this tracker at a
+    /// particular height.
+    pub fn balance_at(&self, height: u32) -> u64 {
+        self.full_txouts()
+            .filter(|(_, full_txout)| full_txout.is_spendable_at(height))
+            .map(|(_, full_txout)| full_txout.txout.value)
+            .sum()
+    }
+}
+
+impl<K, P> Default for KeychainTracker<K, P> {
+    fn default() -> Self {
+        Self {
+            txout_index: Default::default(),
+            chain_graph: Default::default(),
+        }
+    }
+}
+
+impl<K, P> AsRef<SparseChain<P>> for KeychainTracker<K, P> {
+    fn as_ref(&self) -> &SparseChain<P> {
+        self.chain_graph.chain()
+    }
+}
+
+impl<K, P> AsRef<TxGraph> for KeychainTracker<K, P> {
+    fn as_ref(&self) -> &TxGraph {
+        self.chain_graph.graph()
+    }
+}
+
+impl<K, P> AsRef<ChainGraph<P>> for KeychainTracker<K, P> {
+    fn as_ref(&self) -> &ChainGraph<P> {
+        &self.chain_graph
+    }
+}
--- a/crates/chain/src/keychain/txout_index.rs
+++ b/crates/chain/src/keychain/txout_index.rs
@@ -1,18 +1,17 @@
 use crate::{
    collections::*,
-    indexed_tx_graph::Indexer,
    miniscript::{Descriptor, DescriptorPublicKey},
-    spk_iter::BIP32_MAX_INDEX,
-    ForEachTxOut, SpkIterator, SpkTxOutIndex,
+    ForEachTxOut, SpkTxOutIndex,
 };
-use alloc::vec::Vec;
-use bitcoin::{OutPoint, Script, TxOut};
+use alloc::{borrow::Cow, vec::Vec};
+use bitcoin::{secp256k1::Secp256k1, OutPoint, Script, TxOut};
 use core::{fmt::Debug, ops::Deref};

-use crate::Append;
-
 use super::DerivationAdditions;

+/// Maximum [BIP32](https://bips.xyz/32) derivation index.
+pub const BIP32_MAX_INDEX: u32 = (1 << 31) - 1;
+
 /// A convenient wrapper around [`SpkTxOutIndex`] that relates script pubkeys to miniscript public
 /// [`Descriptor`]s.
 ///
@@ -89,26 +88,6 @@ impl<K> Deref for KeychainTxOutIndex<K> {
    }
 }

-impl<K: Clone + Ord + Debug> Indexer for KeychainTxOutIndex<K> {
-    type Additions = DerivationAdditions<K>;
-
-    fn index_txout(&mut self, outpoint: OutPoint, txout: &TxOut) -> Self::Additions {
-        self.scan_txout(outpoint, txout)
-    }
-
-    fn index_tx(&mut self, tx: &bitcoin::Transaction) -> Self::Additions {
-        self.scan(tx)
-    }
-
-    fn apply_additions(&mut self, additions: Self::Additions) {
-        self.apply_additions(additions)
-    }
-
-    fn is_tx_relevant(&self, tx: &bitcoin::Transaction) -> bool {
-        self.is_relevant(tx)
-    }
-}
-
 impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
    /// Scans an object for relevant outpoints, which are stored and indexed internally.
    ///
@@ -147,11 +126,6 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
        &self.inner
    }

-    /// Get a reference to the set of indexed outpoints.
-    pub fn outpoints(&self) -> &BTreeSet<((K, u32), OutPoint)> {
-        self.inner.outpoints()
-    }
-
    /// Return a reference to the internal map of the keychain to descriptors.
    pub fn keychains(&self) -> &BTreeMap<K, Descriptor<DescriptorPublicKey>> {
        &self.keychains
@@ -166,10 +140,7 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
    ///
    /// This will panic if a different `descriptor` is introduced to the same `keychain`.
    pub fn add_keychain(&mut self, keychain: K, descriptor: Descriptor<DescriptorPublicKey>) {
-        let old_descriptor = &*self
-            .keychains
-            .entry(keychain)
-            .or_insert_with(|| descriptor.clone());
+        let old_descriptor = &*self.keychains.entry(keychain).or_insert(descriptor.clone());
        assert_eq!(
            &descriptor, old_descriptor,
            "keychain already contains a different descriptor"
@@ -243,9 +214,10 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
        let next_reveal_index = self.last_revealed.get(keychain).map_or(0, |v| *v + 1);
        let lookahead = self.lookahead.get(keychain).map_or(0, |v| *v);

-        for (new_index, new_spk) in
-            SpkIterator::new_with_range(descriptor, next_store_index..next_reveal_index + lookahead)
-        {
+        for (new_index, new_spk) in range_descriptor_spks(
+            Cow::Borrowed(descriptor),
+            next_store_index..next_reveal_index + lookahead,
+        ) {
            let _inserted = self
                .inner
                .insert_spk((keychain.clone(), new_index), new_spk);
@@ -265,13 +237,13 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
    /// derivable script pubkeys.
    pub fn spks_of_all_keychains(
        &self,
-    ) -> BTreeMap<K, SpkIterator<Descriptor<DescriptorPublicKey>>> {
+    ) -> BTreeMap<K, impl Iterator<Item = (u32, Script)> + Clone> {
        self.keychains
            .iter()
            .map(|(keychain, descriptor)| {
                (
                    keychain.clone(),
-                    SpkIterator::new_with_range(descriptor.clone(), 0..),
+                    range_descriptor_spks(Cow::Owned(descriptor.clone()), 0..),
                )
            })
            .collect()
@@ -283,13 +255,13 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
    /// # Panics
    ///
    /// This will panic if the `keychain` does not exist.
-    pub fn spks_of_keychain(&self, keychain: &K) -> SpkIterator<Descriptor<DescriptorPublicKey>> {
+    pub fn spks_of_keychain(&self, keychain: &K) -> impl Iterator<Item = (u32, Script)> + Clone {
        let descriptor = self
            .keychains
            .get(keychain)
            .expect("keychain must exist")
            .clone();
-        SpkIterator::new_with_range(descriptor, 0..)
+        range_descriptor_spks(Cow::Owned(descriptor), 0..)
    }

    /// Convenience method to get [`revealed_spks_of_keychain`] of all keychains.
@@ -369,7 +341,7 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
        &mut self,
        keychains: &BTreeMap<K, u32>,
    ) -> (
-        BTreeMap<K, SpkIterator<Descriptor<DescriptorPublicKey>>>,
+        BTreeMap<K, impl Iterator<Item = (u32, Script)>>,
        DerivationAdditions<K>,
    ) {
        let mut additions = DerivationAdditions::default();
@@ -379,7 +351,7 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
            let (new_spks, new_additions) = self.reveal_to_target(keychain, index);
            if !new_additions.is_empty() {
                spks.insert(keychain.clone(), new_spks);
-                additions.append(new_additions.clone());
+                additions.append(new_additions);
            }
        }

@@ -404,10 +376,7 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
        &mut self,
        keychain: &K,
        target_index: u32,
-    ) -> (
-        SpkIterator<Descriptor<DescriptorPublicKey>>,
-        DerivationAdditions<K>,
-    ) {
+    ) -> (impl Iterator<Item = (u32, Script)>, DerivationAdditions<K>) {
        let descriptor = self.keychains.get(keychain).expect("keychain must exist");
        let has_wildcard = descriptor.has_wildcard();

@@ -432,7 +401,7 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {

        // we range over indexes that are not stored
        let range = next_reveal_index + lookahead..=target_index + lookahead;
-        for (new_index, new_spk) in SpkIterator::new_with_range(descriptor, range) {
+        for (new_index, new_spk) in range_descriptor_spks(Cow::Borrowed(descriptor), range) {
            let _inserted = self
                .inner
                .insert_spk((keychain.clone(), new_index), new_spk);
@@ -449,13 +418,16 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
                let _old_index = self.last_revealed.insert(keychain.clone(), index);
                debug_assert!(_old_index < Some(index));
                (
-                    SpkIterator::new_with_range(descriptor.clone(), next_reveal_index..index + 1),
+                    range_descriptor_spks(
+                        Cow::Owned(descriptor.clone()),
+                        next_reveal_index..index + 1,
+                    ),
                    DerivationAdditions(core::iter::once((keychain.clone(), index)).collect()),
                )
            }
            None => (
-                SpkIterator::new_with_range(
-                    descriptor.clone(),
+                range_descriptor_spks(
+                    Cow::Owned(descriptor.clone()),
                    next_reveal_index..next_reveal_index,
                ),
                DerivationAdditions::default(),
@@ -586,3 +558,33 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
        let _ = self.reveal_to_target_multi(&additions.0);
    }
 }
+
+fn range_descriptor_spks<'a, R>(
+    descriptor: Cow<'a, Descriptor<DescriptorPublicKey>>,
+    range: R,
+) -> impl Iterator<Item = (u32, Script)> + Clone + Send + 'a
+where
+    R: Iterator<Item = u32> + Clone + Send + 'a,
+{
+    let secp = Secp256k1::verification_only();
+    let has_wildcard = descriptor.has_wildcard();
+    range
+        .into_iter()
+        // non-wildcard descriptors can only have one derivation index (0)
+        .take_while(move |&index| has_wildcard || index == 0)
+        // we can only iterate over non-hardened indices
+        .take_while(|&index| index <= BIP32_MAX_INDEX)
+        .map(
+            move |index| -> Result<_, miniscript::descriptor::ConversionError> {
+                Ok((
+                    index,
+                    descriptor
+                        .at_derivation_index(index)
+                        .derived_descriptor(&secp)?
+                        .script_pubkey(),
+                ))
+            },
+        )
+        .take_while(Result::is_ok)
+        .map(Result::unwrap)
+}
--- a/crates/chain/src/lib.rs
+++ b/crates/chain/src/lib.rs
@@ -17,27 +17,18 @@
 //!    cache or how you fetch it.
 //!
 //! [Bitcoin Dev Kit]: https://bitcoindevkit.org/
-
 #![no_std]
-#![warn(missing_docs)]
-
 pub use bitcoin;
+pub mod chain_graph;
 mod spk_txout_index;
 pub use spk_txout_index::*;
 mod chain_data;
 pub use chain_data::*;
-pub mod indexed_tx_graph;
-pub use indexed_tx_graph::IndexedTxGraph;
 pub mod keychain;
-pub mod local_chain;
+pub mod sparse_chain;
 mod tx_data_traits;
 pub mod tx_graph;
 pub use tx_data_traits::*;
-pub use tx_graph::TxGraph;
-mod chain_oracle;
-pub use chain_oracle::*;
-mod persist;
-pub use persist::*;

 #[doc(hidden)]
 pub mod example_utils;
@@ -48,10 +39,6 @@ pub use miniscript;
 mod descriptor_ext;
 #[cfg(feature = "miniscript")]
 pub use descriptor_ext::DescriptorExt;
-#[cfg(feature = "miniscript")]
-mod spk_iter;
-#[cfg(feature = "miniscript")]
-pub use spk_iter::*;

 #[allow(unused_imports)]
 #[macro_use]
--- a/crates/chain/src/local_chain.rs
+++ b/crates/chain/src/local_chain.rs
@@ -1,250 +0,0 @@
-//! The [`LocalChain`] is a local implementation of [`ChainOracle`].
-
-use core::convert::Infallible;
-
-use alloc::collections::BTreeMap;
-use bitcoin::BlockHash;
-
-use crate::{BlockId, ChainOracle};
-
-/// This is a local implementation of [`ChainOracle`].
-#[derive(Debug, Default, Clone, PartialEq, Eq, PartialOrd, Ord)]
-pub struct LocalChain {
-    blocks: BTreeMap<u32, BlockHash>,
-}
-
-impl ChainOracle for LocalChain {
-    type Error = Infallible;
-
-    fn is_block_in_chain(
-        &self,
-        block: BlockId,
-        static_block: BlockId,
-    ) -> Result<Option<bool>, Self::Error> {
-        if block.height > static_block.height {
-            return Ok(None);
-        }
-        Ok(
-            match (
-                self.blocks.get(&block.height),
-                self.blocks.get(&static_block.height),
-            ) {
-                (Some(&hash), Some(&static_hash)) => {
-                    Some(hash == block.hash && static_hash == static_block.hash)
-                }
-                _ => None,
-            },
-        )
-    }
-
-    fn get_chain_tip(&self) -> Result<Option<BlockId>, Self::Error> {
-        Ok(self.tip())
-    }
-}
-
-impl AsRef<BTreeMap<u32, BlockHash>> for LocalChain {
-    fn as_ref(&self) -> &BTreeMap<u32, BlockHash> {
-        &self.blocks
-    }
-}
-
-impl From<LocalChain> for BTreeMap<u32, BlockHash> {
-    fn from(value: LocalChain) -> Self {
-        value.blocks
-    }
-}
-
-impl From<BTreeMap<u32, BlockHash>> for LocalChain {
-    fn from(value: BTreeMap<u32, BlockHash>) -> Self {
-        Self { blocks: value }
-    }
-}
-
-impl LocalChain {
-    /// Contruct a [`LocalChain`] from a list of [`BlockId`]s.
-    pub fn from_blocks<B>(blocks: B) -> Self
-    where
-        B: IntoIterator<Item = BlockId>,
-    {
-        Self {
-            blocks: blocks.into_iter().map(|b| (b.height, b.hash)).collect(),
-        }
-    }
-
-    /// Get a reference to a map of block height to hash.
-    pub fn blocks(&self) -> &BTreeMap<u32, BlockHash> {
-        &self.blocks
-    }
-
-    /// Get the chain tip.
-    pub fn tip(&self) -> Option<BlockId> {
-        self.blocks
-            .iter()
-            .last()
-            .map(|(&height, &hash)| BlockId { height, hash })
-    }
-
-    /// This is like the sparsechain's logic, expect we must guarantee that all invalidated heights
-    /// are to be re-filled.
-    pub fn determine_changeset(&self, update: &Self) -> Result<ChangeSet, UpdateNotConnectedError> {
-        let update = update.as_ref();
-        let update_tip = match update.keys().last().cloned() {
-            Some(tip) => tip,
-            None => return Ok(ChangeSet::default()),
-        };
-
-        // this is the latest height where both the update and local chain has the same block hash
-        let agreement_height = update
-            .iter()
-            .rev()
-            .find(|&(u_height, u_hash)| self.blocks.get(u_height) == Some(u_hash))
-            .map(|(&height, _)| height);
-
-        // the lower bound of the range to invalidate
-        let invalidate_lb = match agreement_height {
-            Some(height) if height == update_tip => u32::MAX,
-            Some(height) => height + 1,
-            None => 0,
-        };
-
-        // the first block's height to invalidate in the local chain
-        let invalidate_from_height = self.blocks.range(invalidate_lb..).next().map(|(&h, _)| h);
-
-        // the first block of height to invalidate (if any) should be represented in the update
-        if let Some(first_invalid_height) = invalidate_from_height {
-            if !update.contains_key(&first_invalid_height) {
-                return Err(UpdateNotConnectedError(first_invalid_height));
-            }
-        }
-
-        let mut changeset: BTreeMap<u32, Option<BlockHash>> = match invalidate_from_height {
-            Some(first_invalid_height) => {
-                // the first block of height to invalidate should be represented in the update
-                if !update.contains_key(&first_invalid_height) {
-                    return Err(UpdateNotConnectedError(first_invalid_height));
-                }
-                self.blocks
-                    .range(first_invalid_height..)
-                    .map(|(height, _)| (*height, None))
-                    .collect()
-            }
-            None => BTreeMap::new(),
-        };
-        for (height, update_hash) in update {
-            let original_hash = self.blocks.get(height);
-            if Some(update_hash) != original_hash {
-                changeset.insert(*height, Some(*update_hash));
-            }
-        }
-
-        Ok(changeset)
-    }
-
-    /// Applies the given `changeset`.
-    pub fn apply_changeset(&mut self, changeset: ChangeSet) {
-        for (height, blockhash) in changeset {
-            match blockhash {
-                Some(blockhash) => self.blocks.insert(height, blockhash),
-                None => self.blocks.remove(&height),
-            };
-        }
-    }
-
-    /// Updates [`LocalChain`] with an update [`LocalChain`].
-    ///
-    /// This is equivalent to calling [`determine_changeset`] and [`apply_changeset`] in sequence.
-    ///
-    /// [`determine_changeset`]: Self::determine_changeset
-    /// [`apply_changeset`]: Self::apply_changeset
-    pub fn apply_update(&mut self, update: Self) -> Result<ChangeSet, UpdateNotConnectedError> {
-        let changeset = self.determine_changeset(&update)?;
-        self.apply_changeset(changeset.clone());
-        Ok(changeset)
-    }
-
-    /// Derives a [`ChangeSet`] that assumes that there are no preceding changesets.
-    ///
-    /// The changeset returned will record additions of all blocks included in [`Self`].
-    pub fn initial_changeset(&self) -> ChangeSet {
-        self.blocks
-            .iter()
-            .map(|(&height, &hash)| (height, Some(hash)))
-            .collect()
-    }
-
-    /// Insert a block of [`BlockId`] into the [`LocalChain`].
-    ///
-    /// # Error
-    ///
-    /// If the insertion height already contains a block, and the block has a different blockhash,
-    /// this will result in an [`InsertBlockNotMatchingError`].
-    pub fn insert_block(
-        &mut self,
-        block_id: BlockId,
-    ) -> Result<ChangeSet, InsertBlockNotMatchingError> {
-        let mut update = Self::from_blocks(self.tip());
-
-        if let Some(original_hash) = update.blocks.insert(block_id.height, block_id.hash) {
-            if original_hash != block_id.hash {
-                return Err(InsertBlockNotMatchingError {
-                    height: block_id.height,
-                    original_hash,
-                    update_hash: block_id.hash,
-                });
-            }
-        }
-
-        Ok(self.apply_update(update).expect("should always connect"))
-    }
-}
-
-/// This is the return value of [`determine_changeset`] and represents changes to [`LocalChain`].
-///
-/// [`determine_changeset`]: LocalChain::determine_changeset
-pub type ChangeSet = BTreeMap<u32, Option<BlockHash>>;
-
-/// Represents an update failure of [`LocalChain`] due to the update not connecting to the original
-/// chain.
-///
-/// The update cannot be applied to the chain because the chain suffix it represents did not
-/// connect to the existing chain. This error case contains the checkpoint height to include so
-/// that the chains can connect.
-#[derive(Clone, Debug, PartialEq)]
-pub struct UpdateNotConnectedError(pub u32);
-
-impl core::fmt::Display for UpdateNotConnectedError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        write!(
-            f,
-            "the update cannot connect with the chain, try include block at height {}",
-            self.0
-        )
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for UpdateNotConnectedError {}
-
-/// Represents a failure when trying to insert a checkpoint into [`LocalChain`].
-#[derive(Clone, Debug, PartialEq)]
-pub struct InsertBlockNotMatchingError {
-    /// The checkpoints' height.
-    pub height: u32,
-    /// Original checkpoint's block hash.
-    pub original_hash: BlockHash,
-    /// Update checkpoint's block hash.
-    pub update_hash: BlockHash,
-}
-
-impl core::fmt::Display for InsertBlockNotMatchingError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        write!(
-            f,
-            "failed to insert block at height {} as blockhashes conflict: original={}, update={}",
-            self.height, self.original_hash, self.update_hash
-        )
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for InsertBlockNotMatchingError {}
--- a/crates/chain/src/persist.rs
+++ b/crates/chain/src/persist.rs
@@ -1,97 +0,0 @@
-use core::convert::Infallible;
-
-use crate::Append;
-
-/// `Persist` wraps a [`PersistBackend`] (`B`) to create a convenient staging area for changes (`C`)
-/// before they are persisted.
-///
-/// Not all changes to the in-memory representation needs to be written to disk right away, so
-/// [`Persist::stage`] can be used to *stage* changes first and then [`Persist::commit`] can be used
-/// to write changes to disk.
-#[derive(Debug)]
-pub struct Persist<B, C> {
-    backend: B,
-    stage: C,
-}
-
-impl<B, C> Persist<B, C>
-where
-    B: PersistBackend<C>,
-    C: Default + Append,
-{
-    /// Create a new [`Persist`] from [`PersistBackend`].
-    pub fn new(backend: B) -> Self {
-        Self {
-            backend,
-            stage: Default::default(),
-        }
-    }
-
-    /// Stage a `changeset` to be commited later with [`commit`].
-    ///
-    /// [`commit`]: Self::commit
-    pub fn stage(&mut self, changeset: C) {
-        self.stage.append(changeset)
-    }
-
-    /// Get the changes that have not been commited yet.
-    pub fn staged(&self) -> &C {
-        &self.stage
-    }
-
-    /// Commit the staged changes to the underlying persistance backend.
-    ///
-    /// Changes that are committed (if any) are returned.
-    ///
-    /// # Error
-    ///
-    /// Returns a backend-defined error if this fails.
-    pub fn commit(&mut self) -> Result<Option<C>, B::WriteError> {
-        if self.stage.is_empty() {
-            return Ok(None);
-        }
-        self.backend
-            .write_changes(&self.stage)
-            // if written successfully, take and return `self.stage`
-            .map(|_| Some(core::mem::take(&mut self.stage)))
-    }
-}
-
-/// A persistence backend for [`Persist`].
-///
-/// `C` represents the changeset; a datatype that records changes made to in-memory data structures
-/// that are to be persisted, or retrieved from persistence.
-pub trait PersistBackend<C> {
-    /// The error the backend returns when it fails to write.
-    type WriteError: core::fmt::Debug;
-
-    /// The error the backend returns when it fails to load changesets `C`.
-    type LoadError: core::fmt::Debug;
-
-    /// Writes a changeset to the persistence backend.
-    ///
-    /// It is up to the backend what it does with this. It could store every changeset in a list or
-    /// it inserts the actual changes into a more structured database. All it needs to guarantee is
-    /// that [`load_from_persistence`] restores a keychain tracker to what it should be if all
-    /// changesets had been applied sequentially.
-    ///
-    /// [`load_from_persistence`]: Self::load_from_persistence
-    fn write_changes(&mut self, changeset: &C) -> Result<(), Self::WriteError>;
-
-    /// Return the aggregate changeset `C` from persistence.
-    fn load_from_persistence(&mut self) -> Result<C, Self::LoadError>;
-}
-
-impl<C: Default> PersistBackend<C> for () {
-    type WriteError = Infallible;
-
-    type LoadError = Infallible;
-
-    fn write_changes(&mut self, _changeset: &C) -> Result<(), Self::WriteError> {
-        Ok(())
-    }
-
-    fn load_from_persistence(&mut self) -> Result<C, Self::LoadError> {
-        Ok(C::default())
-    }
-}
--- a/crates/chain/src/sparse_chain.rs
+++ b/crates/chain/src/sparse_chain.rs
--- a/crates/chain/src/spk_iter.rs
+++ b/crates/chain/src/spk_iter.rs
@@ -1,215 +0,0 @@
-use crate::{
-    bitcoin::{secp256k1::Secp256k1, Script},
-    miniscript::{Descriptor, DescriptorPublicKey},
-};
-use core::{borrow::Borrow, ops::Bound, ops::RangeBounds};
-
-/// Maximum [BIP32](https://bips.xyz/32) derivation index.
-pub const BIP32_MAX_INDEX: u32 = (1 << 31) - 1;
-
-/// An iterator for derived script pubkeys.
-///
-/// [`SpkIterator`] is an implementation of the [`Iterator`] trait which possesses its own `next()`
-/// and `nth()` functions, both of which circumvent the unnecessary intermediate derivations required
-/// when using their default implementations.
-///
-/// ## Examples
-///
-/// ```
-/// use bdk_chain::SpkIterator;
-/// # use miniscript::{Descriptor, DescriptorPublicKey};
-/// # use bitcoin::{secp256k1::Secp256k1};
-/// # use std::str::FromStr;
-/// # let secp = bitcoin::secp256k1::Secp256k1::signing_only();
-/// # let (descriptor, _) = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, "wpkh([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/1/0)").unwrap();
-/// # let external_spk_0 = descriptor.at_derivation_index(0).script_pubkey();
-/// # let external_spk_3 = descriptor.at_derivation_index(3).script_pubkey();
-/// # let external_spk_4 = descriptor.at_derivation_index(4).script_pubkey();
-///
-/// // Creates a new script pubkey iterator starting at 0 from a descriptor.
-/// let mut spk_iter = SpkIterator::new(&descriptor);
-/// assert_eq!(spk_iter.next(), Some((0, external_spk_0)));
-/// assert_eq!(spk_iter.next(), None);
-/// ```
-#[derive(Clone)]
-pub struct SpkIterator<D> {
-    next_index: u32,
-    end: u32,
-    descriptor: D,
-    secp: Secp256k1<bitcoin::secp256k1::VerifyOnly>,
-}
-
-impl<D> SpkIterator<D>
-where
-    D: Borrow<Descriptor<DescriptorPublicKey>>,
-{
-    /// Creates a new script pubkey iterator starting at 0 from a descriptor.
-    pub fn new(descriptor: D) -> Self {
-        let end = if descriptor.borrow().has_wildcard() {
-            BIP32_MAX_INDEX
-        } else {
-            0
-        };
-
-        SpkIterator::new_with_range(descriptor, 0..=end)
-    }
-
-    // Creates a new script pubkey iterator from a descriptor with a given range.
-    pub(crate) fn new_with_range<R>(descriptor: D, range: R) -> Self
-    where
-        R: RangeBounds<u32>,
-    {
-        let mut end = match range.end_bound() {
-            Bound::Included(end) => *end + 1,
-            Bound::Excluded(end) => *end,
-            Bound::Unbounded => u32::MAX,
-        };
-        // Because `end` is exclusive, we want the maximum value to be BIP32_MAX_INDEX + 1.
-        end = end.min(BIP32_MAX_INDEX + 1);
-
-        Self {
-            next_index: match range.start_bound() {
-                Bound::Included(start) => *start,
-                Bound::Excluded(start) => *start + 1,
-                Bound::Unbounded => u32::MIN,
-            },
-            end,
-            descriptor,
-            secp: Secp256k1::verification_only(),
-        }
-    }
-}
-
-impl<D> Iterator for SpkIterator<D>
-where
-    D: Borrow<Descriptor<DescriptorPublicKey>>,
-{
-    type Item = (u32, Script);
-
-    fn next(&mut self) -> Option<Self::Item> {
-        // For non-wildcard descriptors, we expect the first element to be Some((0, spk)), then None after.
-        // For wildcard descriptors, we expect it to keep iterating until exhausted.
-        if self.next_index >= self.end {
-            return None;
-        }
-
-        let script = self
-            .descriptor
-            .borrow()
-            .at_derivation_index(self.next_index)
-            .derived_descriptor(&self.secp)
-            .expect("the descriptor cannot need hardened derivation")
-            .script_pubkey();
-        let output = (self.next_index, script);
-
-        self.next_index += 1;
-
-        Some(output)
-    }
-
-    fn nth(&mut self, n: usize) -> Option<Self::Item> {
-        self.next_index = self
-            .next_index
-            .saturating_add(u32::try_from(n).unwrap_or(u32::MAX));
-        self.next()
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use crate::{
-        bitcoin::secp256k1::Secp256k1,
-        keychain::KeychainTxOutIndex,
-        miniscript::{Descriptor, DescriptorPublicKey},
-        spk_iter::{SpkIterator, BIP32_MAX_INDEX},
-    };
-
-    #[derive(Clone, Debug, PartialEq, Eq, Ord, PartialOrd)]
-    enum TestKeychain {
-        External,
-        Internal,
-    }
-
-    fn init_txout_index() -> (
-        KeychainTxOutIndex<TestKeychain>,
-        Descriptor<DescriptorPublicKey>,
-        Descriptor<DescriptorPublicKey>,
-    ) {
-        let mut txout_index = KeychainTxOutIndex::<TestKeychain>::default();
-
-        let secp = Secp256k1::signing_only();
-        let (external_descriptor,_) = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, "tr([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/0/*)").unwrap();
-        let (internal_descriptor,_) = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, "tr([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/1/*)").unwrap();
-
-        txout_index.add_keychain(TestKeychain::External, external_descriptor.clone());
-        txout_index.add_keychain(TestKeychain::Internal, internal_descriptor.clone());
-
-        (txout_index, external_descriptor, internal_descriptor)
-    }
-
-    #[test]
-    #[allow(clippy::iter_nth_zero)]
-    fn test_spkiterator_wildcard() {
-        let (_, external_desc, _) = init_txout_index();
-        let external_spk_0 = external_desc.at_derivation_index(0).script_pubkey();
-        let external_spk_16 = external_desc.at_derivation_index(16).script_pubkey();
-        let external_spk_20 = external_desc.at_derivation_index(20).script_pubkey();
-        let external_spk_21 = external_desc.at_derivation_index(21).script_pubkey();
-        let external_spk_max = external_desc
-            .at_derivation_index(BIP32_MAX_INDEX)
-            .script_pubkey();
-
-        let mut external_spk = SpkIterator::new(&external_desc);
-        let max_index = BIP32_MAX_INDEX - 22;
-
-        assert_eq!(external_spk.next().unwrap(), (0, external_spk_0));
-        assert_eq!(external_spk.nth(15).unwrap(), (16, external_spk_16));
-        assert_eq!(external_spk.nth(3).unwrap(), (20, external_spk_20.clone()));
-        assert_eq!(external_spk.next().unwrap(), (21, external_spk_21));
-        assert_eq!(
-            external_spk.nth(max_index as usize).unwrap(),
-            (BIP32_MAX_INDEX, external_spk_max)
-        );
-        assert_eq!(external_spk.nth(0), None);
-
-        let mut external_spk = SpkIterator::new_with_range(&external_desc, 0..21);
-        assert_eq!(external_spk.nth(20).unwrap(), (20, external_spk_20));
-        assert_eq!(external_spk.next(), None);
-
-        let mut external_spk = SpkIterator::new_with_range(&external_desc, 0..21);
-        assert_eq!(external_spk.nth(21), None);
-    }
-
-    #[test]
-    #[allow(clippy::iter_nth_zero)]
-    fn test_spkiterator_non_wildcard() {
-        let secp = bitcoin::secp256k1::Secp256k1::signing_only();
-        let (no_wildcard_descriptor, _) = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, "wpkh([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/1/0)").unwrap();
-        let external_spk_0 = no_wildcard_descriptor
-            .at_derivation_index(0)
-            .script_pubkey();
-
-        let mut external_spk = SpkIterator::new(&no_wildcard_descriptor);
-
-        assert_eq!(external_spk.next().unwrap(), (0, external_spk_0.clone()));
-        assert_eq!(external_spk.next(), None);
-
-        let mut external_spk = SpkIterator::new(&no_wildcard_descriptor);
-
-        assert_eq!(external_spk.nth(0).unwrap(), (0, external_spk_0));
-        assert_eq!(external_spk.nth(0), None);
-    }
-
-    // The following dummy traits were created to test if SpkIterator is working properly.
-    trait TestSendStatic: Send + 'static {
-        fn test(&self) -> u32 {
-            20
-        }
-    }
-
-    impl TestSendStatic for SpkIterator<Descriptor<DescriptorPublicKey>> {
-        fn test(&self) -> u32 {
-            20
-        }
-    }
-}
--- a/crates/chain/src/spk_txout_index.rs
+++ b/crates/chain/src/spk_txout_index.rs
@@ -2,7 +2,6 @@ use core::ops::RangeBounds;

 use crate::{
    collections::{hash_map::Entry, BTreeMap, BTreeSet, HashMap},
-    indexed_tx_graph::Indexer,
    ForEachTxOut,
 };
 use bitcoin::{self, OutPoint, Script, Transaction, TxOut, Txid};
@@ -20,13 +19,13 @@ use bitcoin::{self, OutPoint, Script, Transaction, TxOut, Txid};
 /// Note there is no harm in scanning transactions that disappear from the blockchain or were never
 /// in there in the first place. `SpkTxOutIndex` is intentionally *monotone* -- you cannot delete or
 /// modify txouts that have been indexed. To find out which txouts from the index are actually in the
-/// chain or unspent, you must use other sources of information like a [`TxGraph`].
+/// chain or unspent, you must use other sources of information like a [`SparseChain`].
 ///
 /// [`TxOut`]: bitcoin::TxOut
 /// [`insert_spk`]: Self::insert_spk
 /// [`Ord`]: core::cmp::Ord
 /// [`scan`]: Self::scan
-/// [`TxGraph`]: crate::tx_graph::TxGraph
+/// [`SparseChain`]: crate::sparse_chain::SparseChain
 #[derive(Clone, Debug)]
 pub struct SpkTxOutIndex<I> {
    /// script pubkeys ordered by index
@@ -53,28 +52,6 @@ impl<I> Default for SpkTxOutIndex<I> {
    }
 }

-impl<I: Clone + Ord> Indexer for SpkTxOutIndex<I> {
-    type Additions = ();
-
-    fn index_txout(&mut self, outpoint: OutPoint, txout: &TxOut) -> Self::Additions {
-        self.scan_txout(outpoint, txout);
-        Default::default()
-    }
-
-    fn index_tx(&mut self, tx: &Transaction) -> Self::Additions {
-        self.scan(tx);
-        Default::default()
-    }
-
-    fn apply_additions(&mut self, _additions: Self::Additions) {
-        // This applies nothing.
-    }
-
-    fn is_tx_relevant(&self, tx: &Transaction) -> bool {
-        self.is_relevant(tx)
-    }
-}
-
 /// This macro is used instead of a member function of `SpkTxOutIndex`, which would result in a
 /// compiler error[E0521]: "borrowed data escapes out of closure" when we attempt to take a
 /// reference out of the `ForEachTxOut` closure during scanning.
@@ -120,11 +97,6 @@ impl<I: Clone + Ord> SpkTxOutIndex<I> {
        scan_txout!(self, op, txout)
    }

-    /// Get a reference to the set of indexed outpoints.
-    pub fn outpoints(&self) -> &BTreeSet<(I, OutPoint)> {
-        &self.spk_txouts
-    }
-
    /// Iterate over all known txouts that spend to tracked script pubkeys.
    pub fn txouts(
        &self,
--- a/crates/chain/src/tx_data_traits.rs
+++ b/crates/chain/src/tx_data_traits.rs
@@ -1,7 +1,3 @@
-use crate::collections::BTreeMap;
-use crate::collections::BTreeSet;
-use crate::BlockId;
-use alloc::vec::Vec;
 use bitcoin::{Block, OutPoint, Transaction, TxOut};

 /// Trait to do something with every txout contained in a structure.
@@ -35,86 +31,3 @@ impl ForEachTxOut for Transaction {
        }
    }
 }
-
-/// Trait that "anchors" blockchain data to a specific block of height and hash.
-///
-/// I.e. If transaction A is anchored in block B, then if block B is in the best chain, we can
-/// assume that transaction A is also confirmed in the best chain. This does not necessarily mean
-/// that transaction A is confirmed in block B. It could also mean transaction A is confirmed in a
-/// parent block of B.
-pub trait Anchor: core::fmt::Debug + Clone + Eq + PartialOrd + Ord + core::hash::Hash {
-    /// Returns the [`BlockId`] that the associated blockchain data is "anchored" in.
-    fn anchor_block(&self) -> BlockId;
-
-    /// Get the upper bound of the chain data's confirmation height.
-    ///
-    /// The default definition gives a pessimistic answer. This can be overridden by the `Anchor`
-    /// implementation for a more accurate value.
-    fn confirmation_height_upper_bound(&self) -> u32 {
-        self.anchor_block().height
-    }
-}
-
-impl<A: Anchor> Anchor for &'static A {
-    fn anchor_block(&self) -> BlockId {
-        <A as Anchor>::anchor_block(self)
-    }
-}
-
-/// Trait that makes an object appendable.
-pub trait Append {
-    /// Append another object of the same type onto `self`.
-    fn append(&mut self, other: Self);
-
-    /// Returns whether the structure is considered empty.
-    fn is_empty(&self) -> bool;
-}
-
-impl Append for () {
-    fn append(&mut self, _other: Self) {}
-
-    fn is_empty(&self) -> bool {
-        true
-    }
-}
-
-impl<K: Ord, V> Append for BTreeMap<K, V> {
-    fn append(&mut self, mut other: Self) {
-        BTreeMap::append(self, &mut other)
-    }
-
-    fn is_empty(&self) -> bool {
-        BTreeMap::is_empty(self)
-    }
-}
-
-impl<T: Ord> Append for BTreeSet<T> {
-    fn append(&mut self, mut other: Self) {
-        BTreeSet::append(self, &mut other)
-    }
-
-    fn is_empty(&self) -> bool {
-        BTreeSet::is_empty(self)
-    }
-}
-
-impl<T> Append for Vec<T> {
-    fn append(&mut self, mut other: Self) {
-        Vec::append(self, &mut other)
-    }
-
-    fn is_empty(&self) -> bool {
-        Vec::is_empty(self)
-    }
-}
-
-impl<A: Append, B: Append> Append for (A, B) {
-    fn append(&mut self, other: Self) {
-        Append::append(&mut self.0, other.0);
-        Append::append(&mut self.1, other.1);
-    }
-
-    fn is_empty(&self) -> bool {
-        Append::is_empty(&self.0) && Append::is_empty(&self.1)
-    }
-}
--- a/crates/chain/src/tx_graph.rs
+++ b/crates/chain/src/tx_graph.rs
--- a/crates/chain/tests/common/mod.rs
+++ b/crates/chain/tests/common/mod.rs
@@ -5,14 +5,6 @@ macro_rules! h {
    }};
 }

-#[allow(unused_macros)]
-macro_rules! local_chain {
-    [ $(($height:expr, $block_hash:expr)), * ] => {{
-        #[allow(unused_mut)]
-        bdk_chain::local_chain::LocalChain::from_blocks([$(($height, $block_hash).into()),*])
-    }};
-}
-
 #[allow(unused_macros)]
 macro_rules! chain {
    ($([$($tt:tt)*]),*) => { chain!( checkpoints: [$([$($tt)*]),*] ) };
--- a/crates/chain/tests/test_chain_graph.rs
+++ b/crates/chain/tests/test_chain_graph.rs
@@ -0,0 +1,653 @@
+#[macro_use]
+mod common;
+
+use bdk_chain::{
+    chain_graph::*,
+    collections::HashSet,
+    sparse_chain,
+    tx_graph::{self, TxGraph},
+    BlockId, TxHeight,
+};
+use bitcoin::{OutPoint, PackedLockTime, Script, Sequence, Transaction, TxIn, TxOut, Witness};
+
+#[test]
+fn test_spent_by() {
+    let tx1 = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![],
+        output: vec![TxOut::default()],
+    };
+
+    let op = OutPoint {
+        txid: tx1.txid(),
+        vout: 0,
+    };
+
+    let tx2 = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![TxIn {
+            previous_output: op,
+            ..Default::default()
+        }],
+        output: vec![],
+    };
+    let tx3 = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(42),
+        input: vec![TxIn {
+            previous_output: op,
+            ..Default::default()
+        }],
+        output: vec![],
+    };
+
+    let mut cg1 = ChainGraph::default();
+    let _ = cg1
+        .insert_tx(tx1, TxHeight::Unconfirmed)
+        .expect("should insert");
+    let mut cg2 = cg1.clone();
+    let _ = cg1
+        .insert_tx(tx2.clone(), TxHeight::Unconfirmed)
+        .expect("should insert");
+    let _ = cg2
+        .insert_tx(tx3.clone(), TxHeight::Unconfirmed)
+        .expect("should insert");
+
+    assert_eq!(cg1.spent_by(op), Some((&TxHeight::Unconfirmed, tx2.txid())));
+    assert_eq!(cg2.spent_by(op), Some((&TxHeight::Unconfirmed, tx3.txid())));
+}
+
+#[test]
+fn update_evicts_conflicting_tx() {
+    let cp_a = BlockId {
+        height: 0,
+        hash: h!("A"),
+    };
+    let cp_b = BlockId {
+        height: 1,
+        hash: h!("B"),
+    };
+    let cp_b2 = BlockId {
+        height: 1,
+        hash: h!("B'"),
+    };
+
+    let tx_a = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![],
+        output: vec![TxOut::default()],
+    };
+
+    let tx_b = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![TxIn {
+            previous_output: OutPoint::new(tx_a.txid(), 0),
+            script_sig: Script::new(),
+            sequence: Sequence::default(),
+            witness: Witness::new(),
+        }],
+        output: vec![TxOut::default()],
+    };
+
+    let tx_b2 = Transaction {
+        version: 0x02,
+        lock_time: PackedLockTime(0),
+        input: vec![TxIn {
+            previous_output: OutPoint::new(tx_a.txid(), 0),
+            script_sig: Script::new(),
+            sequence: Sequence::default(),
+            witness: Witness::new(),
+        }],
+        output: vec![TxOut::default(), TxOut::default()],
+    };
+    {
+        let mut cg1 = {
+            let mut cg = ChainGraph::default();
+            let _ = cg.insert_checkpoint(cp_a).expect("should insert cp");
+            let _ = cg
+                .insert_tx(tx_a.clone(), TxHeight::Confirmed(0))
+                .expect("should insert tx");
+            let _ = cg
+                .insert_tx(tx_b.clone(), TxHeight::Unconfirmed)
+                .expect("should insert tx");
+            cg
+        };
+        let cg2 = {
+            let mut cg = ChainGraph::default();
+            let _ = cg
+                .insert_tx(tx_b2.clone(), TxHeight::Unconfirmed)
+                .expect("should insert tx");
+            cg
+        };
+
+        let changeset = ChangeSet::<TxHeight> {
+            chain: sparse_chain::ChangeSet {
+                checkpoints: Default::default(),
+                txids: [
+                    (tx_b.txid(), None),
+                    (tx_b2.txid(), Some(TxHeight::Unconfirmed)),
+                ]
+                .into(),
+            },
+            graph: tx_graph::Additions {
+                tx: [tx_b2.clone()].into(),
+                txout: [].into(),
+            },
+        };
+        assert_eq!(
+            cg1.determine_changeset(&cg2),
+            Ok(changeset.clone()),
+            "tx should be evicted from mempool"
+        );
+
+        cg1.apply_changeset(changeset);
+    }
+
+    {
+        let cg1 = {
+            let mut cg = ChainGraph::default();
+            let _ = cg.insert_checkpoint(cp_a).expect("should insert cp");
+            let _ = cg.insert_checkpoint(cp_b).expect("should insert cp");
+            let _ = cg
+                .insert_tx(tx_a.clone(), TxHeight::Confirmed(0))
+                .expect("should insert tx");
+            let _ = cg
+                .insert_tx(tx_b.clone(), TxHeight::Confirmed(1))
+                .expect("should insert tx");
+            cg
+        };
+        let cg2 = {
+            let mut cg = ChainGraph::default();
+            let _ = cg
+                .insert_tx(tx_b2.clone(), TxHeight::Unconfirmed)
+                .expect("should insert tx");
+            cg
+        };
+        assert_eq!(
+            cg1.determine_changeset(&cg2),
+            Err(UpdateError::UnresolvableConflict(UnresolvableConflict {
+                already_confirmed_tx: (TxHeight::Confirmed(1), tx_b.txid()),
+                update_tx: (TxHeight::Unconfirmed, tx_b2.txid()),
+            })),
+            "fail if tx is evicted from valid block"
+        );
+    }
+
+    {
+        // Given 2 blocks `{A, B}`, and an update that invalidates block B with
+        // `{A, B'}`, we expect txs that exist in `B` that conflicts with txs
+        // introduced in the update to be successfully evicted.
+        let mut cg1 = {
+            let mut cg = ChainGraph::default();
+            let _ = cg.insert_checkpoint(cp_a).expect("should insert cp");
+            let _ = cg.insert_checkpoint(cp_b).expect("should insert cp");
+            let _ = cg
+                .insert_tx(tx_a, TxHeight::Confirmed(0))
+                .expect("should insert tx");
+            let _ = cg
+                .insert_tx(tx_b.clone(), TxHeight::Confirmed(1))
+                .expect("should insert tx");
+            cg
+        };
+        let cg2 = {
+            let mut cg = ChainGraph::default();
+            let _ = cg.insert_checkpoint(cp_a).expect("should insert cp");
+            let _ = cg.insert_checkpoint(cp_b2).expect("should insert cp");
+            let _ = cg
+                .insert_tx(tx_b2.clone(), TxHeight::Unconfirmed)
+                .expect("should insert tx");
+            cg
+        };
+
+        let changeset = ChangeSet::<TxHeight> {
+            chain: sparse_chain::ChangeSet {
+                checkpoints: [(1, Some(h!("B'")))].into(),
+                txids: [
+                    (tx_b.txid(), None),
+                    (tx_b2.txid(), Some(TxHeight::Unconfirmed)),
+                ]
+                .into(),
+            },
+            graph: tx_graph::Additions {
+                tx: [tx_b2].into(),
+                txout: [].into(),
+            },
+        };
+        assert_eq!(
+            cg1.determine_changeset(&cg2),
+            Ok(changeset.clone()),
+            "tx should be evicted from B",
+        );
+
+        cg1.apply_changeset(changeset);
+    }
+}
+
+#[test]
+fn chain_graph_new_missing() {
+    let tx_a = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![],
+        output: vec![TxOut::default()],
+    };
+    let tx_b = Transaction {
+        version: 0x02,
+        lock_time: PackedLockTime(0),
+        input: vec![],
+        output: vec![TxOut::default()],
+    };
+
+    let update = chain!(
+        index: TxHeight,
+        checkpoints: [[0, h!("A")]],
+        txids: [
+            (tx_a.txid(), TxHeight::Confirmed(0)),
+            (tx_b.txid(), TxHeight::Confirmed(0))
+        ]
+    );
+    let mut graph = TxGraph::default();
+
+    let mut expected_missing = HashSet::new();
+    expected_missing.insert(tx_a.txid());
+    expected_missing.insert(tx_b.txid());
+
+    assert_eq!(
+        ChainGraph::new(update.clone(), graph.clone()),
+        Err(NewError::Missing(expected_missing.clone()))
+    );
+
+    let _ = graph.insert_tx(tx_b.clone());
+    expected_missing.remove(&tx_b.txid());
+
+    assert_eq!(
+        ChainGraph::new(update.clone(), graph.clone()),
+        Err(NewError::Missing(expected_missing.clone()))
+    );
+
+    let _ = graph.insert_txout(
+        OutPoint {
+            txid: tx_a.txid(),
+            vout: 0,
+        },
+        tx_a.output[0].clone(),
+    );
+
+    assert_eq!(
+        ChainGraph::new(update.clone(), graph.clone()),
+        Err(NewError::Missing(expected_missing)),
+        "inserting an output instead of full tx doesn't satisfy constraint"
+    );
+
+    let _ = graph.insert_tx(tx_a.clone());
+
+    let new_graph = ChainGraph::new(update.clone(), graph.clone()).unwrap();
+    let expected_graph = {
+        let mut cg = ChainGraph::<TxHeight>::default();
+        let _ = cg
+            .insert_checkpoint(update.latest_checkpoint().unwrap())
+            .unwrap();
+        let _ = cg.insert_tx(tx_a, TxHeight::Confirmed(0)).unwrap();
+        let _ = cg.insert_tx(tx_b, TxHeight::Confirmed(0)).unwrap();
+        cg
+    };
+
+    assert_eq!(new_graph, expected_graph);
+}
+
+#[test]
+fn chain_graph_new_conflicts() {
+    let tx_a = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![],
+        output: vec![TxOut::default()],
+    };
+
+    let tx_b = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![TxIn {
+            previous_output: OutPoint::new(tx_a.txid(), 0),
+            script_sig: Script::new(),
+            sequence: Sequence::default(),
+            witness: Witness::new(),
+        }],
+        output: vec![TxOut::default()],
+    };
+
+    let tx_b2 = Transaction {
+        version: 0x02,
+        lock_time: PackedLockTime(0),
+        input: vec![TxIn {
+            previous_output: OutPoint::new(tx_a.txid(), 0),
+            script_sig: Script::new(),
+            sequence: Sequence::default(),
+            witness: Witness::new(),
+        }],
+        output: vec![TxOut::default(), TxOut::default()],
+    };
+
+    let chain = chain!(
+        index: TxHeight,
+        checkpoints: [[5, h!("A")]],
+        txids: [
+            (tx_a.txid(), TxHeight::Confirmed(1)),
+            (tx_b.txid(), TxHeight::Confirmed(2)),
+            (tx_b2.txid(), TxHeight::Confirmed(3))
+        ]
+    );
+
+    let graph = TxGraph::new([tx_a, tx_b, tx_b2]);
+
+    assert!(matches!(
+        ChainGraph::new(chain, graph),
+        Err(NewError::Conflict { .. })
+    ));
+}
+
+#[test]
+fn test_get_tx_in_chain() {
+    let mut cg = ChainGraph::default();
+    let tx = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![],
+        output: vec![TxOut::default()],
+    };
+
+    let _ = cg.insert_tx(tx.clone(), TxHeight::Unconfirmed).unwrap();
+    assert_eq!(
+        cg.get_tx_in_chain(tx.txid()),
+        Some((&TxHeight::Unconfirmed, &tx))
+    );
+}
+
+#[test]
+fn test_iterate_transactions() {
+    let mut cg = ChainGraph::default();
+    let txs = (0..3)
+        .map(|i| Transaction {
+            version: i,
+            lock_time: PackedLockTime(0),
+            input: vec![],
+            output: vec![TxOut::default()],
+        })
+        .collect::<Vec<_>>();
+    let _ = cg
+        .insert_checkpoint(BlockId {
+            height: 1,
+            hash: h!("A"),
+        })
+        .unwrap();
+    let _ = cg
+        .insert_tx(txs[0].clone(), TxHeight::Confirmed(1))
+        .unwrap();
+    let _ = cg.insert_tx(txs[1].clone(), TxHeight::Unconfirmed).unwrap();
+    let _ = cg
+        .insert_tx(txs[2].clone(), TxHeight::Confirmed(0))
+        .unwrap();
+
+    assert_eq!(
+        cg.transactions_in_chain().collect::<Vec<_>>(),
+        vec![
+            (&TxHeight::Confirmed(0), &txs[2]),
+            (&TxHeight::Confirmed(1), &txs[0]),
+            (&TxHeight::Unconfirmed, &txs[1]),
+        ]
+    );
+}
+
+/// Start with: block1, block2a, tx1, tx2a
+///   Update 1: block2a -> block2b , tx2a -> tx2b
+///   Update 2: block2b -> block2c , tx2b -> tx2a
+#[test]
+fn test_apply_changes_reintroduce_tx() {
+    let block1 = BlockId {
+        height: 1,
+        hash: h!("block 1"),
+    };
+    let block2a = BlockId {
+        height: 2,
+        hash: h!("block 2a"),
+    };
+    let block2b = BlockId {
+        height: 2,
+        hash: h!("block 2b"),
+    };
+    let block2c = BlockId {
+        height: 2,
+        hash: h!("block 2c"),
+    };
+
+    let tx1 = Transaction {
+        version: 0,
+        lock_time: PackedLockTime(1),
+        input: Vec::new(),
+        output: [TxOut {
+            value: 1,
+            script_pubkey: Script::new(),
+        }]
+        .into(),
+    };
+
+    let tx2a = Transaction {
+        version: 0,
+        lock_time: PackedLockTime('a'.into()),
+        input: [TxIn {
+            previous_output: OutPoint::new(tx1.txid(), 0),
+            ..Default::default()
+        }]
+        .into(),
+        output: [TxOut {
+            value: 0,
+            ..Default::default()
+        }]
+        .into(),
+    };
+
+    let tx2b = Transaction {
+        lock_time: PackedLockTime('b'.into()),
+        ..tx2a.clone()
+    };
+
+    // block1, block2a, tx1, tx2a
+    let mut cg = {
+        let mut cg = ChainGraph::default();
+        let _ = cg.insert_checkpoint(block1).unwrap();
+        let _ = cg.insert_checkpoint(block2a).unwrap();
+        let _ = cg.insert_tx(tx1, TxHeight::Confirmed(1)).unwrap();
+        let _ = cg.insert_tx(tx2a.clone(), TxHeight::Confirmed(2)).unwrap();
+        cg
+    };
+
+    // block2a -> block2b , tx2a -> tx2b
+    let update = {
+        let mut update = ChainGraph::default();
+        let _ = update.insert_checkpoint(block1).unwrap();
+        let _ = update.insert_checkpoint(block2b).unwrap();
+        let _ = update
+            .insert_tx(tx2b.clone(), TxHeight::Confirmed(2))
+            .unwrap();
+        update
+    };
+    assert_eq!(
+        cg.apply_update(update).expect("should update"),
+        ChangeSet {
+            chain: changeset! {
+                checkpoints: [(2, Some(block2b.hash))],
+                txids: [(tx2a.txid(), None), (tx2b.txid(), Some(TxHeight::Confirmed(2)))]
+            },
+            graph: tx_graph::Additions {
+                tx: [tx2b.clone()].into(),
+                ..Default::default()
+            },
+        }
+    );
+
+    // block2b -> block2c , tx2b -> tx2a
+    let update = {
+        let mut update = ChainGraph::default();
+        let _ = update.insert_checkpoint(block1).unwrap();
+        let _ = update.insert_checkpoint(block2c).unwrap();
+        let _ = update
+            .insert_tx(tx2a.clone(), TxHeight::Confirmed(2))
+            .unwrap();
+        update
+    };
+    assert_eq!(
+        cg.apply_update(update).expect("should update"),
+        ChangeSet {
+            chain: changeset! {
+                checkpoints: [(2, Some(block2c.hash))],
+                txids: [(tx2b.txid(), None), (tx2a.txid(), Some(TxHeight::Confirmed(2)))]
+            },
+            ..Default::default()
+        }
+    );
+}
+
+#[test]
+fn test_evict_descendants() {
+    let block_1 = BlockId {
+        height: 1,
+        hash: h!("block 1"),
+    };
+
+    let block_2a = BlockId {
+        height: 2,
+        hash: h!("block 2 a"),
+    };
+
+    let block_2b = BlockId {
+        height: 2,
+        hash: h!("block 2 b"),
+    };
+
+    let tx_1 = Transaction {
+        input: vec![TxIn {
+            previous_output: OutPoint::new(h!("fake tx"), 0),
+            ..Default::default()
+        }],
+        output: vec![TxOut {
+            value: 10_000,
+            script_pubkey: Script::new(),
+        }],
+        ..common::new_tx(1)
+    };
+    let tx_2 = Transaction {
+        input: vec![TxIn {
+            previous_output: OutPoint::new(tx_1.txid(), 0),
+            ..Default::default()
+        }],
+        output: vec![
+            TxOut {
+                value: 20_000,
+                script_pubkey: Script::new(),
+            },
+            TxOut {
+                value: 30_000,
+                script_pubkey: Script::new(),
+            },
+        ],
+        ..common::new_tx(2)
+    };
+    let tx_3 = Transaction {
+        input: vec![TxIn {
+            previous_output: OutPoint::new(tx_2.txid(), 0),
+            ..Default::default()
+        }],
+        output: vec![TxOut {
+            value: 40_000,
+            script_pubkey: Script::new(),
+        }],
+        ..common::new_tx(3)
+    };
+    let tx_4 = Transaction {
+        input: vec![TxIn {
+            previous_output: OutPoint::new(tx_2.txid(), 1),
+            ..Default::default()
+        }],
+        output: vec![TxOut {
+            value: 40_000,
+            script_pubkey: Script::new(),
+        }],
+        ..common::new_tx(4)
+    };
+    let tx_5 = Transaction {
+        input: vec![TxIn {
+            previous_output: OutPoint::new(tx_4.txid(), 0),
+            ..Default::default()
+        }],
+        output: vec![TxOut {
+            value: 40_000,
+            script_pubkey: Script::new(),
+        }],
+        ..common::new_tx(5)
+    };
+
+    let tx_conflict = Transaction {
+        input: vec![TxIn {
+            previous_output: OutPoint::new(tx_1.txid(), 0),
+            ..Default::default()
+        }],
+        output: vec![TxOut {
+            value: 12345,
+            script_pubkey: Script::new(),
+        }],
+        ..common::new_tx(6)
+    };
+
+    // 1 is spent by 2, 2 is spent by 3 and 4, 4 is spent by 5
+    let _txid_1 = tx_1.txid();
+    let txid_2 = tx_2.txid();
+    let txid_3 = tx_3.txid();
+    let txid_4 = tx_4.txid();
+    let txid_5 = tx_5.txid();
+
+    // this tx conflicts with 2
+    let txid_conflict = tx_conflict.txid();
+
+    let cg = {
+        let mut cg = ChainGraph::<TxHeight>::default();
+        let _ = cg.insert_checkpoint(block_1);
+        let _ = cg.insert_checkpoint(block_2a);
+        let _ = cg.insert_tx(tx_1, TxHeight::Confirmed(1));
+        let _ = cg.insert_tx(tx_2, TxHeight::Confirmed(2));
+        let _ = cg.insert_tx(tx_3, TxHeight::Confirmed(2));
+        let _ = cg.insert_tx(tx_4, TxHeight::Confirmed(2));
+        let _ = cg.insert_tx(tx_5, TxHeight::Confirmed(2));
+        cg
+    };
+
+    let update = {
+        let mut cg = ChainGraph::<TxHeight>::default();
+        let _ = cg.insert_checkpoint(block_1);
+        let _ = cg.insert_checkpoint(block_2b);
+        let _ = cg.insert_tx(tx_conflict.clone(), TxHeight::Confirmed(2));
+        cg
+    };
+
+    assert_eq!(
+        cg.determine_changeset(&update),
+        Ok(ChangeSet {
+            chain: changeset! {
+                checkpoints: [(2, Some(block_2b.hash))],
+                txids: [(txid_2, None), (txid_3, None), (txid_4, None), (txid_5, None), (txid_conflict, Some(TxHeight::Confirmed(2)))]
+            },
+            graph: tx_graph::Additions {
+                tx: [tx_conflict.clone()].into(),
+                ..Default::default()
+            }
+        })
+    );
+
+    let err = cg
+        .insert_tx_preview(tx_conflict, TxHeight::Unconfirmed)
+        .expect_err("must fail due to conflicts");
+    assert!(matches!(err, InsertTxError::UnresolvableConflict(_)));
+}
--- a/crates/chain/tests/test_indexed_tx_graph.rs
+++ b/crates/chain/tests/test_indexed_tx_graph.rs
@@ -1,467 +0,0 @@
-#[macro_use]
-mod common;
-
-use std::collections::{BTreeMap, BTreeSet};
-
-use bdk_chain::{
-    indexed_tx_graph::{IndexedAdditions, IndexedTxGraph},
-    keychain::{Balance, DerivationAdditions, KeychainTxOutIndex},
-    local_chain::LocalChain,
-    tx_graph::Additions,
-    BlockId, ChainPosition, ConfirmationHeightAnchor,
-};
-use bitcoin::{secp256k1::Secp256k1, BlockHash, OutPoint, Script, Transaction, TxIn, TxOut};
-use miniscript::Descriptor;
-
-/// Ensure [`IndexedTxGraph::insert_relevant_txs`] can successfully index transactions NOT presented
-/// in topological order.
-///
-/// Given 3 transactions (A, B, C), where A has 2 owned outputs. B and C spends an output each of A.
-/// Typically, we would only know whether B and C are relevant if we have indexed A (A's outpoints
-/// are associated with owned spks in the index). Ensure insertion and indexing is topological-
-/// agnostic.
-#[test]
-fn insert_relevant_txs() {
-    const DESCRIPTOR: &str = "tr([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/0/*)";
-    let (descriptor, _) = Descriptor::parse_descriptor(&Secp256k1::signing_only(), DESCRIPTOR)
-        .expect("must be valid");
-    let spk_0 = descriptor.at_derivation_index(0).script_pubkey();
-    let spk_1 = descriptor.at_derivation_index(9).script_pubkey();
-
-    let mut graph = IndexedTxGraph::<ConfirmationHeightAnchor, KeychainTxOutIndex<()>>::default();
-    graph.index.add_keychain((), descriptor);
-    graph.index.set_lookahead(&(), 10);
-
-    let tx_a = Transaction {
-        output: vec![
-            TxOut {
-                value: 10_000,
-                script_pubkey: spk_0,
-            },
-            TxOut {
-                value: 20_000,
-                script_pubkey: spk_1,
-            },
-        ],
-        ..common::new_tx(0)
-    };
-
-    let tx_b = Transaction {
-        input: vec![TxIn {
-            previous_output: OutPoint::new(tx_a.txid(), 0),
-            ..Default::default()
-        }],
-        ..common::new_tx(1)
-    };
-
-    let tx_c = Transaction {
-        input: vec![TxIn {
-            previous_output: OutPoint::new(tx_a.txid(), 1),
-            ..Default::default()
-        }],
-        ..common::new_tx(2)
-    };
-
-    let txs = [tx_c, tx_b, tx_a];
-
-    assert_eq!(
-        graph.insert_relevant_txs(txs.iter().map(|tx| (tx, None)), None),
-        IndexedAdditions {
-            graph_additions: Additions {
-                txs: txs.into(),
-                ..Default::default()
-            },
-            index_additions: DerivationAdditions([((), 9_u32)].into()),
-        }
-    )
-}
-
-#[test]
-/// Ensure consistency IndexedTxGraph list_* and balance methods. These methods lists
-/// relevant txouts and utxos from the information fetched from a ChainOracle (here a LocalChain).
-///
-/// Test Setup:
-///
-/// Local Chain =>  <0> ----- <1> ----- <2> ----- <3> ---- ... ---- <150>
-///
-/// Keychains:
-///
-/// keychain_1: Trusted
-/// keychain_2: Untrusted
-///
-/// Transactions:
-///
-/// tx1: A Coinbase, sending 70000 sats to "trusted" address. [Block 0]
-/// tx2: A external Receive, sending 30000 sats to "untrusted" address. [Block 1]
-/// tx3: Internal Spend. Spends tx2 and returns change of 10000 to "trusted" address. [Block 2]
-/// tx4: Mempool tx, sending 20000 sats to "trusted" address.
-/// tx5: Mempool tx, sending 15000 sats to "untested" address.
-/// tx6: Complete unrelated tx. [Block 3]
-///
-/// Different transactions are added via `insert_relevant_txs`.
-/// `list_owned_txout`, `list_owned_utxos` and `balance` method is asserted
-/// with expected values at Block height 0, 1, and 2.
-///
-/// Finally Add more blocks to local chain until tx1 coinbase maturity hits.
-/// Assert maturity at coinbase maturity inflection height. Block height 98 and 99.
-
-fn test_list_owned_txouts() {
-    // Create Local chains
-
-    let local_chain = (0..150)
-        .map(|i| (i as u32, h!("random")))
-        .collect::<BTreeMap<u32, BlockHash>>();
-    let local_chain = LocalChain::from(local_chain);
-
-    // Initiate IndexedTxGraph
-
-    let (desc_1, _) = Descriptor::parse_descriptor(&Secp256k1::signing_only(), "tr(tprv8ZgxMBicQKsPd3krDUsBAmtnRsK3rb8u5yi1zhQgMhF1tR8MW7xfE4rnrbbsrbPR52e7rKapu6ztw1jXveJSCGHEriUGZV7mCe88duLp5pj/86'/1'/0'/0/*)").unwrap();
-    let (desc_2, _) = Descriptor::parse_descriptor(&Secp256k1::signing_only(), "tr(tprv8ZgxMBicQKsPd3krDUsBAmtnRsK3rb8u5yi1zhQgMhF1tR8MW7xfE4rnrbbsrbPR52e7rKapu6ztw1jXveJSCGHEriUGZV7mCe88duLp5pj/86'/1'/0'/1/*)").unwrap();
-
-    let mut graph =
-        IndexedTxGraph::<ConfirmationHeightAnchor, KeychainTxOutIndex<String>>::default();
-
-    graph.index.add_keychain("keychain_1".into(), desc_1);
-    graph.index.add_keychain("keychain_2".into(), desc_2);
-    graph.index.set_lookahead_for_all(10);
-
-    // Get trusted and untrusted addresses
-
-    let mut trusted_spks = Vec::new();
-    let mut untrusted_spks = Vec::new();
-
-    {
-        // we need to scope here to take immutanble reference of the graph
-        for _ in 0..10 {
-            let ((_, script), _) = graph.index.reveal_next_spk(&"keychain_1".to_string());
-            // TODO Assert indexes
-            trusted_spks.push(script.clone());
-        }
-    }
-    {
-        for _ in 0..10 {
-            let ((_, script), _) = graph.index.reveal_next_spk(&"keychain_2".to_string());
-            untrusted_spks.push(script.clone());
-        }
-    }
-
-    // Create test transactions
-
-    // tx1 is the genesis coinbase
-    let tx1 = Transaction {
-        input: vec![TxIn {
-            previous_output: OutPoint::null(),
-            ..Default::default()
-        }],
-        output: vec![TxOut {
-            value: 70000,
-            script_pubkey: trusted_spks[0].clone(),
-        }],
-        ..common::new_tx(0)
-    };
-
-    // tx2 is an incoming transaction received at untrusted keychain at block 1.
-    let tx2 = Transaction {
-        output: vec![TxOut {
-            value: 30000,
-            script_pubkey: untrusted_spks[0].clone(),
-        }],
-        ..common::new_tx(0)
-    };
-
-    // tx3 spends tx2 and gives a change back in trusted keychain. Confirmed at Block 2.
-    let tx3 = Transaction {
-        input: vec![TxIn {
-            previous_output: OutPoint::new(tx2.txid(), 0),
-            ..Default::default()
-        }],
-        output: vec![TxOut {
-            value: 10000,
-            script_pubkey: trusted_spks[1].clone(),
-        }],
-        ..common::new_tx(0)
-    };
-
-    // tx4 is an external transaction receiving at untrusted keychain, unconfirmed.
-    let tx4 = Transaction {
-        output: vec![TxOut {
-            value: 20000,
-            script_pubkey: untrusted_spks[1].clone(),
-        }],
-        ..common::new_tx(0)
-    };
-
-    // tx5 is spending tx3 and receiving change at trusted keychain, unconfirmed.
-    let tx5 = Transaction {
-        output: vec![TxOut {
-            value: 15000,
-            script_pubkey: trusted_spks[2].clone(),
-        }],
-        ..common::new_tx(0)
-    };
-
-    // tx6 is an unrelated transaction confirmed at 3.
-    let tx6 = common::new_tx(0);
-
-    // Insert transactions into graph with respective anchors
-    // For unconfirmed txs we pass in `None`.
-
-    let _ = graph.insert_relevant_txs(
-        [&tx1, &tx2, &tx3, &tx6].iter().enumerate().map(|(i, tx)| {
-            let height = i as u32;
-            (
-                *tx,
-                local_chain
-                    .blocks()
-                    .get(&height)
-                    .map(|&hash| BlockId { height, hash })
-                    .map(|anchor_block| ConfirmationHeightAnchor {
-                        anchor_block,
-                        confirmation_height: anchor_block.height,
-                    }),
-            )
-        }),
-        None,
-    );
-
-    let _ = graph.insert_relevant_txs([&tx4, &tx5].iter().map(|tx| (*tx, None)), Some(100));
-
-    // A helper lambda to extract and filter data from the graph.
-    let fetch =
-        |height: u32,
-         graph: &IndexedTxGraph<ConfirmationHeightAnchor, KeychainTxOutIndex<String>>| {
-            let chain_tip = local_chain
-                .blocks()
-                .get(&height)
-                .map(|&hash| BlockId { height, hash })
-                .expect("block must exist");
-            let txouts = graph
-                .graph()
-                .filter_chain_txouts(
-                    &local_chain,
-                    chain_tip,
-                    graph.index.outpoints().iter().cloned(),
-                )
-                .collect::<Vec<_>>();
-
-            let utxos = graph
-                .graph()
-                .filter_chain_unspents(
-                    &local_chain,
-                    chain_tip,
-                    graph.index.outpoints().iter().cloned(),
-                )
-                .collect::<Vec<_>>();
-
-            let balance = graph.graph().balance(
-                &local_chain,
-                chain_tip,
-                graph.index.outpoints().iter().cloned(),
-                |_, spk: &Script| trusted_spks.contains(spk),
-            );
-
-            assert_eq!(txouts.len(), 5);
-            assert_eq!(utxos.len(), 4);
-
-            let confirmed_txouts_txid = txouts
-                .iter()
-                .filter_map(|(_, full_txout)| {
-                    if matches!(full_txout.chain_position, ChainPosition::Confirmed(_)) {
-                        Some(full_txout.outpoint.txid)
-                    } else {
-                        None
-                    }
-                })
-                .collect::<BTreeSet<_>>();
-
-            let unconfirmed_txouts_txid = txouts
-                .iter()
-                .filter_map(|(_, full_txout)| {
-                    if matches!(full_txout.chain_position, ChainPosition::Unconfirmed(_)) {
-                        Some(full_txout.outpoint.txid)
-                    } else {
-                        None
-                    }
-                })
-                .collect::<BTreeSet<_>>();
-
-            let confirmed_utxos_txid = utxos
-                .iter()
-                .filter_map(|(_, full_txout)| {
-                    if matches!(full_txout.chain_position, ChainPosition::Confirmed(_)) {
-                        Some(full_txout.outpoint.txid)
-                    } else {
-                        None
-                    }
-                })
-                .collect::<BTreeSet<_>>();
-
-            let unconfirmed_utxos_txid = utxos
-                .iter()
-                .filter_map(|(_, full_txout)| {
-                    if matches!(full_txout.chain_position, ChainPosition::Unconfirmed(_)) {
-                        Some(full_txout.outpoint.txid)
-                    } else {
-                        None
-                    }
-                })
-                .collect::<BTreeSet<_>>();
-
-            (
-                confirmed_txouts_txid,
-                unconfirmed_txouts_txid,
-                confirmed_utxos_txid,
-                unconfirmed_utxos_txid,
-                balance,
-            )
-        };
-
-    // ----- TEST BLOCK -----
-
-    // AT Block 0
-    {
-        let (
-            confirmed_txouts_txid,
-            unconfirmed_txouts_txid,
-            confirmed_utxos_txid,
-            unconfirmed_utxos_txid,
-            balance,
-        ) = fetch(0, &graph);
-
-        assert_eq!(confirmed_txouts_txid, [tx1.txid()].into());
-        assert_eq!(
-            unconfirmed_txouts_txid,
-            [tx2.txid(), tx3.txid(), tx4.txid(), tx5.txid()].into()
-        );
-
-        assert_eq!(confirmed_utxos_txid, [tx1.txid()].into());
-        assert_eq!(
-            unconfirmed_utxos_txid,
-            [tx3.txid(), tx4.txid(), tx5.txid()].into()
-        );
-
-        assert_eq!(
-            balance,
-            Balance {
-                immature: 70000,          // immature coinbase
-                trusted_pending: 25000,   // tx3 + tx5
-                untrusted_pending: 20000, // tx4
-                confirmed: 0              // Nothing is confirmed yet
-            }
-        );
-    }
-
-    // AT Block 1
-    {
-        let (
-            confirmed_txouts_txid,
-            unconfirmed_txouts_txid,
-            confirmed_utxos_txid,
-            unconfirmed_utxos_txid,
-            balance,
-        ) = fetch(1, &graph);
-
-        // tx2 gets into confirmed txout set
-        assert_eq!(confirmed_txouts_txid, [tx1.txid(), tx2.txid()].into());
-        assert_eq!(
-            unconfirmed_txouts_txid,
-            [tx3.txid(), tx4.txid(), tx5.txid()].into()
-        );
-
-        // tx2 doesn't get into confirmed utxos set
-        assert_eq!(confirmed_utxos_txid, [tx1.txid()].into());
-        assert_eq!(
-            unconfirmed_utxos_txid,
-            [tx3.txid(), tx4.txid(), tx5.txid()].into()
-        );
-
-        assert_eq!(
-            balance,
-            Balance {
-                immature: 70000,          // immature coinbase
-                trusted_pending: 25000,   // tx3 + tx5
-                untrusted_pending: 20000, // tx4
-                confirmed: 0              // Nothing is confirmed yet
-            }
-        );
-    }
-
-    // AT Block 2
-    {
-        let (
-            confirmed_txouts_txid,
-            unconfirmed_txouts_txid,
-            confirmed_utxos_txid,
-            unconfirmed_utxos_txid,
-            balance,
-        ) = fetch(2, &graph);
-
-        // tx3 now gets into the confirmed txout set
-        assert_eq!(
-            confirmed_txouts_txid,
-            [tx1.txid(), tx2.txid(), tx3.txid()].into()
-        );
-        assert_eq!(unconfirmed_txouts_txid, [tx4.txid(), tx5.txid()].into());
-
-        // tx3 also gets into confirmed utxo set
-        assert_eq!(confirmed_utxos_txid, [tx1.txid(), tx3.txid()].into());
-        assert_eq!(unconfirmed_utxos_txid, [tx4.txid(), tx5.txid()].into());
-
-        assert_eq!(
-            balance,
-            Balance {
-                immature: 70000,          // immature coinbase
-                trusted_pending: 15000,   // tx5
-                untrusted_pending: 20000, // tx4
-                confirmed: 10000          // tx3 got confirmed
-            }
-        );
-    }
-
-    // AT Block 98
-    {
-        let (
-            confirmed_txouts_txid,
-            unconfirmed_txouts_txid,
-            confirmed_utxos_txid,
-            unconfirmed_utxos_txid,
-            balance,
-        ) = fetch(98, &graph);
-
-        assert_eq!(
-            confirmed_txouts_txid,
-            [tx1.txid(), tx2.txid(), tx3.txid()].into()
-        );
-        assert_eq!(unconfirmed_txouts_txid, [tx4.txid(), tx5.txid()].into());
-
-        assert_eq!(confirmed_utxos_txid, [tx1.txid(), tx3.txid()].into());
-        assert_eq!(unconfirmed_utxos_txid, [tx4.txid(), tx5.txid()].into());
-
-        // Coinbase is still immature
-        assert_eq!(
-            balance,
-            Balance {
-                immature: 70000,          // immature coinbase
-                trusted_pending: 15000,   // tx5
-                untrusted_pending: 20000, // tx4
-                confirmed: 10000          // tx1 got matured
-            }
-        );
-    }
-
-    // AT Block 99
-    {
-        let (_, _, _, _, balance) = fetch(100, &graph);
-
-        // Coinbase maturity hits
-        assert_eq!(
-            balance,
-            Balance {
-                immature: 0,              // coinbase matured
-                trusted_pending: 15000,   // tx5
-                untrusted_pending: 20000, // tx4
-                confirmed: 80000          // tx1 + tx3
-            }
-        );
-    }
-}
--- a/crates/chain/tests/test_keychain_tracker.rs
+++ b/crates/chain/tests/test_keychain_tracker.rs
@@ -0,0 +1,239 @@
+#![cfg(feature = "miniscript")]
+#[macro_use]
+mod common;
+use bdk_chain::{
+    keychain::{Balance, KeychainTracker},
+    miniscript::{
+        bitcoin::{secp256k1::Secp256k1, OutPoint, PackedLockTime, Transaction, TxOut},
+        Descriptor,
+    },
+    BlockId, ConfirmationTime, TxHeight,
+};
+use bitcoin::TxIn;
+
+#[test]
+fn test_insert_tx() {
+    let mut tracker = KeychainTracker::default();
+    let secp = Secp256k1::new();
+    let (descriptor, _) = Descriptor::parse_descriptor(&secp, "tr([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/0/*)").unwrap();
+    tracker.add_keychain((), descriptor.clone());
+    let txout = TxOut {
+        value: 100_000,
+        script_pubkey: descriptor.at_derivation_index(5).script_pubkey(),
+    };
+
+    let tx = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![],
+        output: vec![txout],
+    };
+
+    let _ = tracker.txout_index.reveal_to_target(&(), 5);
+
+    let changeset = tracker
+        .insert_tx_preview(tx.clone(), ConfirmationTime::Unconfirmed)
+        .unwrap();
+    tracker.apply_changeset(changeset);
+    assert_eq!(
+        tracker
+            .chain_graph()
+            .transactions_in_chain()
+            .collect::<Vec<_>>(),
+        vec![(&ConfirmationTime::Unconfirmed, &tx)]
+    );
+
+    assert_eq!(
+        tracker
+            .txout_index
+            .txouts_of_keychain(&())
+            .collect::<Vec<_>>(),
+        vec![(
+            5,
+            OutPoint {
+                txid: tx.txid(),
+                vout: 0
+            }
+        )]
+    );
+}
+
+#[test]
+fn test_balance() {
+    use core::str::FromStr;
+    #[derive(Debug, Clone, PartialEq, Eq, Ord, PartialOrd)]
+    enum Keychain {
+        One,
+        Two,
+    }
+    let mut tracker = KeychainTracker::<Keychain, TxHeight>::default();
+    let one = Descriptor::from_str("tr([73c5da0a/86'/0'/0']xpub6BgBgsespWvERF3LHQu6CnqdvfEvtMcQjYrcRzx53QJjSxarj2afYWcLteoGVky7D3UKDP9QyrLprQ3VCECoY49yfdDEHGCtMMj92pReUsQ/0/*)#rg247h69").unwrap();
+    let two = Descriptor::from_str("tr([73c5da0a/86'/0'/0']xpub6BgBgsespWvERF3LHQu6CnqdvfEvtMcQjYrcRzx53QJjSxarj2afYWcLteoGVky7D3UKDP9QyrLprQ3VCECoY49yfdDEHGCtMMj92pReUsQ/1/*)#ju05rz2a").unwrap();
+    tracker.add_keychain(Keychain::One, one);
+    tracker.add_keychain(Keychain::Two, two);
+
+    let tx1 = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![],
+        output: vec![TxOut {
+            value: 13_000,
+            script_pubkey: tracker
+                .txout_index
+                .reveal_next_spk(&Keychain::One)
+                .0
+                 .1
+                .clone(),
+        }],
+    };
+
+    let tx2 = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![],
+        output: vec![TxOut {
+            value: 7_000,
+            script_pubkey: tracker
+                .txout_index
+                .reveal_next_spk(&Keychain::Two)
+                .0
+                 .1
+                .clone(),
+        }],
+    };
+
+    let tx_coinbase = Transaction {
+        version: 0x01,
+        lock_time: PackedLockTime(0),
+        input: vec![TxIn::default()],
+        output: vec![TxOut {
+            value: 11_000,
+            script_pubkey: tracker
+                .txout_index
+                .reveal_next_spk(&Keychain::Two)
+                .0
+                 .1
+                .clone(),
+        }],
+    };
+
+    assert!(tx_coinbase.is_coin_base());
+
+    let _ = tracker
+        .insert_checkpoint(BlockId {
+            height: 5,
+            hash: h!("1"),
+        })
+        .unwrap();
+
+    let should_trust = |keychain: &Keychain| match *keychain {
+        Keychain::One => false,
+        Keychain::Two => true,
+    };
+
+    assert_eq!(tracker.balance(should_trust), Balance::default());
+
+    let _ = tracker
+        .insert_tx(tx1.clone(), TxHeight::Unconfirmed)
+        .unwrap();
+
+    assert_eq!(
+        tracker.balance(should_trust),
+        Balance {
+            untrusted_pending: 13_000,
+            ..Default::default()
+        }
+    );
+
+    let _ = tracker
+        .insert_tx(tx2.clone(), TxHeight::Unconfirmed)
+        .unwrap();
+
+    assert_eq!(
+        tracker.balance(should_trust),
+        Balance {
+            trusted_pending: 7_000,
+            untrusted_pending: 13_000,
+            ..Default::default()
+        }
+    );
+
+    let _ = tracker
+        .insert_tx(tx_coinbase, TxHeight::Confirmed(0))
+        .unwrap();
+
+    assert_eq!(
+        tracker.balance(should_trust),
+        Balance {
+            trusted_pending: 7_000,
+            untrusted_pending: 13_000,
+            immature: 11_000,
+            ..Default::default()
+        }
+    );
+
+    let _ = tracker.insert_tx(tx1, TxHeight::Confirmed(1)).unwrap();
+
+    assert_eq!(
+        tracker.balance(should_trust),
+        Balance {
+            trusted_pending: 7_000,
+            untrusted_pending: 0,
+            immature: 11_000,
+            confirmed: 13_000,
+        }
+    );
+
+    let _ = tracker.insert_tx(tx2, TxHeight::Confirmed(2)).unwrap();
+
+    assert_eq!(
+        tracker.balance(should_trust),
+        Balance {
+            trusted_pending: 0,
+            untrusted_pending: 0,
+            immature: 11_000,
+            confirmed: 20_000,
+        }
+    );
+
+    let _ = tracker
+        .insert_checkpoint(BlockId {
+            height: 98,
+            hash: h!("98"),
+        })
+        .unwrap();
+
+    assert_eq!(
+        tracker.balance(should_trust),
+        Balance {
+            trusted_pending: 0,
+            untrusted_pending: 0,
+            immature: 11_000,
+            confirmed: 20_000,
+        }
+    );
+
+    let _ = tracker
+        .insert_checkpoint(BlockId {
+            height: 99,
+            hash: h!("99"),
+        })
+        .unwrap();
+
+    assert_eq!(
+        tracker.balance(should_trust),
+        Balance {
+            trusted_pending: 0,
+            untrusted_pending: 0,
+            immature: 0,
+            confirmed: 31_000,
+        }
+    );
+
+    assert_eq!(tracker.balance_at(0), 0);
+    assert_eq!(tracker.balance_at(1), 13_000);
+    assert_eq!(tracker.balance_at(2), 20_000);
+    assert_eq!(tracker.balance_at(98), 20_000);
+    assert_eq!(tracker.balance_at(99), 31_000);
+    assert_eq!(tracker.balance_at(100), 31_000);
+}
--- a/crates/chain/tests/test_keychain_txout_index.rs
+++ b/crates/chain/tests/test_keychain_txout_index.rs
@@ -293,6 +293,7 @@ fn test_wildcard_derivations() {
    let _ = txout_index.reveal_to_target(&TestKeychain::External, 25);

    (0..=15)
+        .into_iter()
        .chain(vec![17, 20, 23].into_iter())
        .for_each(|index| assert!(txout_index.mark_used(&TestKeychain::External, index)));

@@ -309,7 +310,7 @@ fn test_wildcard_derivations() {

    // - Use all the derived till 26.
    // - next_unused() = ((27, <spk>), DerivationAdditions)
-    (0..=26).for_each(|index| {
+    (0..=26).into_iter().for_each(|index| {
        txout_index.mark_used(&TestKeychain::External, index);
    });

--- a/crates/chain/tests/test_local_chain.rs
+++ b/crates/chain/tests/test_local_chain.rs
@@ -1,228 +0,0 @@
-use bdk_chain::local_chain::{
-    ChangeSet, InsertBlockNotMatchingError, LocalChain, UpdateNotConnectedError,
-};
-use bitcoin::BlockHash;
-
-#[macro_use]
-mod common;
-
-#[test]
-fn add_first_tip() {
-    let chain = LocalChain::default();
-    assert_eq!(
-        chain.determine_changeset(&local_chain![(0, h!("A"))]),
-        Ok([(0, Some(h!("A")))].into()),
-        "add first tip"
-    );
-}
-
-#[test]
-fn add_second_tip() {
-    let chain = local_chain![(0, h!("A"))];
-    assert_eq!(
-        chain.determine_changeset(&local_chain![(0, h!("A")), (1, h!("B"))]),
-        Ok([(1, Some(h!("B")))].into())
-    );
-}
-
-#[test]
-fn two_disjoint_chains_cannot_merge() {
-    let chain1 = local_chain![(0, h!("A"))];
-    let chain2 = local_chain![(1, h!("B"))];
-    assert_eq!(
-        chain1.determine_changeset(&chain2),
-        Err(UpdateNotConnectedError(0))
-    );
-}
-
-#[test]
-fn duplicate_chains_should_merge() {
-    let chain1 = local_chain![(0, h!("A"))];
-    let chain2 = local_chain![(0, h!("A"))];
-    assert_eq!(chain1.determine_changeset(&chain2), Ok(Default::default()));
-}
-
-#[test]
-fn can_introduce_older_checkpoints() {
-    let chain1 = local_chain![(2, h!("C")), (3, h!("D"))];
-    let chain2 = local_chain![(1, h!("B")), (2, h!("C"))];
-
-    assert_eq!(
-        chain1.determine_changeset(&chain2),
-        Ok([(1, Some(h!("B")))].into())
-    );
-}
-
-#[test]
-fn fix_blockhash_before_agreement_point() {
-    let chain1 = local_chain![(0, h!("im-wrong")), (1, h!("we-agree"))];
-    let chain2 = local_chain![(0, h!("fix")), (1, h!("we-agree"))];
-
-    assert_eq!(
-        chain1.determine_changeset(&chain2),
-        Ok([(0, Some(h!("fix")))].into())
-    )
-}
-
-/// B and C are in both chain and update
-/// ```
-///        | 0 | 1 | 2 | 3 | 4
-/// chain  |     B   C
-/// update | A   B   C   D
-/// ```
-/// This should succeed with the point of agreement being C and A should be added in addition.
-#[test]
-fn two_points_of_agreement() {
-    let chain1 = local_chain![(1, h!("B")), (2, h!("C"))];
-    let chain2 = local_chain![(0, h!("A")), (1, h!("B")), (2, h!("C")), (3, h!("D"))];
-
-    assert_eq!(
-        chain1.determine_changeset(&chain2),
-        Ok([(0, Some(h!("A"))), (3, Some(h!("D")))].into()),
-    );
-}
-
-/// Update and chain does not connect:
-/// ```
-///        | 0 | 1 | 2 | 3 | 4
-/// chain  |     B   C
-/// update | A   B       D
-/// ```
-/// This should fail as we cannot figure out whether C & D are on the same chain
-#[test]
-fn update_and_chain_does_not_connect() {
-    let chain1 = local_chain![(1, h!("B")), (2, h!("C"))];
-    let chain2 = local_chain![(0, h!("A")), (1, h!("B")), (3, h!("D"))];
-
-    assert_eq!(
-        chain1.determine_changeset(&chain2),
-        Err(UpdateNotConnectedError(2)),
-    );
-}
-
-/// Transient invalidation:
-/// ```
-///        | 0 | 1 | 2 | 3 | 4 | 5
-/// chain  | A       B   C       E
-/// update | A       B'  C'  D
-/// ```
-/// This should succeed and invalidate B,C and E with point of agreement being A.
-#[test]
-fn transitive_invalidation_applies_to_checkpoints_higher_than_invalidation() {
-    let chain1 = local_chain![(0, h!("A")), (2, h!("B")), (3, h!("C")), (5, h!("E"))];
-    let chain2 = local_chain![(0, h!("A")), (2, h!("B'")), (3, h!("C'")), (4, h!("D"))];
-
-    assert_eq!(
-        chain1.determine_changeset(&chain2),
-        Ok([
-            (2, Some(h!("B'"))),
-            (3, Some(h!("C'"))),
-            (4, Some(h!("D"))),
-            (5, None),
-        ]
-        .into())
-    );
-}
-
-/// Transient invalidation:
-/// ```
-///        | 0 | 1 | 2 | 3 | 4
-/// chain  |     B   C       E
-/// update |     B'  C'  D
-/// ```
-///
-/// This should succeed and invalidate B, C and E with no point of agreement
-#[test]
-fn transitive_invalidation_applies_to_checkpoints_higher_than_invalidation_no_point_of_agreement() {
-    let chain1 = local_chain![(1, h!("B")), (2, h!("C")), (4, h!("E"))];
-    let chain2 = local_chain![(1, h!("B'")), (2, h!("C'")), (3, h!("D"))];
-
-    assert_eq!(
-        chain1.determine_changeset(&chain2),
-        Ok([
-            (1, Some(h!("B'"))),
-            (2, Some(h!("C'"))),
-            (3, Some(h!("D"))),
-            (4, None)
-        ]
-        .into())
-    )
-}
-
-/// Transient invalidation:
-/// ```
-///        | 0 | 1 | 2 | 3 | 4
-/// chain  | A   B   C       E
-/// update |     B'  C'  D
-/// ```
-///
-/// This should fail since although it tells us that B and C are invalid it doesn't tell us whether
-/// A was invalid.
-#[test]
-fn invalidation_but_no_connection() {
-    let chain1 = local_chain![(0, h!("A")), (1, h!("B")), (2, h!("C")), (4, h!("E"))];
-    let chain2 = local_chain![(1, h!("B'")), (2, h!("C'")), (3, h!("D"))];
-
-    assert_eq!(
-        chain1.determine_changeset(&chain2),
-        Err(UpdateNotConnectedError(0))
-    )
-}
-
-#[test]
-fn insert_block() {
-    struct TestCase {
-        original: LocalChain,
-        insert: (u32, BlockHash),
-        expected_result: Result<ChangeSet, InsertBlockNotMatchingError>,
-        expected_final: LocalChain,
-    }
-
-    let test_cases = [
-        TestCase {
-            original: local_chain![],
-            insert: (5, h!("block5")),
-            expected_result: Ok([(5, Some(h!("block5")))].into()),
-            expected_final: local_chain![(5, h!("block5"))],
-        },
-        TestCase {
-            original: local_chain![(3, h!("A"))],
-            insert: (4, h!("B")),
-            expected_result: Ok([(4, Some(h!("B")))].into()),
-            expected_final: local_chain![(3, h!("A")), (4, h!("B"))],
-        },
-        TestCase {
-            original: local_chain![(4, h!("B"))],
-            insert: (3, h!("A")),
-            expected_result: Ok([(3, Some(h!("A")))].into()),
-            expected_final: local_chain![(3, h!("A")), (4, h!("B"))],
-        },
-        TestCase {
-            original: local_chain![(2, h!("K"))],
-            insert: (2, h!("K")),
-            expected_result: Ok([].into()),
-            expected_final: local_chain![(2, h!("K"))],
-        },
-        TestCase {
-            original: local_chain![(2, h!("K"))],
-            insert: (2, h!("J")),
-            expected_result: Err(InsertBlockNotMatchingError {
-                height: 2,
-                original_hash: h!("K"),
-                update_hash: h!("J"),
-            }),
-            expected_final: local_chain![(2, h!("K"))],
-        },
-    ];
-
-    for (i, t) in test_cases.into_iter().enumerate() {
-        let mut chain = t.original;
-        assert_eq!(
-            chain.insert_block(t.insert.into()),
-            t.expected_result,
-            "[{}] unexpected result when inserting block",
-            i,
-        );
-        assert_eq!(chain, t.expected_final, "[{}] unexpected final chain", i,);
-    }
-}
--- a/crates/chain/tests/test_sparse_chain.rs
+++ b/crates/chain/tests/test_sparse_chain.rs
@@ -0,0 +1,773 @@
+#[macro_use]
+mod common;
+
+use bdk_chain::{collections::BTreeSet, sparse_chain::*, BlockId, TxHeight};
+use bitcoin::{hashes::Hash, Txid};
+use core::ops::Bound;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
+pub struct TestIndex(TxHeight, u32);
+
+impl ChainPosition for TestIndex {
+    fn height(&self) -> TxHeight {
+        self.0
+    }
+
+    fn max_ord_of_height(height: TxHeight) -> Self {
+        Self(height, u32::MAX)
+    }
+
+    fn min_ord_of_height(height: TxHeight) -> Self {
+        Self(height, u32::MIN)
+    }
+}
+
+impl TestIndex {
+    pub fn new<H>(height: H, ext: u32) -> Self
+    where
+        H: Into<TxHeight>,
+    {
+        Self(height.into(), ext)
+    }
+}
+
+#[test]
+fn add_first_checkpoint() {
+    let chain = SparseChain::default();
+    assert_eq!(
+        chain.determine_changeset(&chain!([0, h!("A")])),
+        Ok(changeset! {
+            checkpoints: [(0, Some(h!("A")))],
+            txids: []
+        },),
+        "add first tip"
+    );
+}
+
+#[test]
+fn add_second_tip() {
+    let chain = chain!([0, h!("A")]);
+    assert_eq!(
+        chain.determine_changeset(&chain!([0, h!("A")], [1, h!("B")])),
+        Ok(changeset! {
+            checkpoints: [(1, Some(h!("B")))],
+            txids: []
+        },),
+        "extend tip by one"
+    );
+}
+
+#[test]
+fn two_disjoint_chains_cannot_merge() {
+    let chain1 = chain!([0, h!("A")]);
+    let chain2 = chain!([1, h!("B")]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Err(UpdateError::NotConnected(0))
+    );
+}
+
+#[test]
+fn duplicate_chains_should_merge() {
+    let chain1 = chain!([0, h!("A")]);
+    let chain2 = chain!([0, h!("A")]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(ChangeSet::default())
+    );
+}
+
+#[test]
+fn duplicate_chains_with_txs_should_merge() {
+    let chain1 = chain!(checkpoints: [[0,h!("A")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    let chain2 = chain!(checkpoints: [[0,h!("A")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(ChangeSet::default())
+    );
+}
+
+#[test]
+fn duplicate_chains_with_different_txs_should_merge() {
+    let chain1 = chain!(checkpoints: [[0,h!("A")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    let chain2 = chain!(checkpoints: [[0,h!("A")]], txids: [(h!("tx1"), TxHeight::Confirmed(0))]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [],
+            txids: [(h!("tx1"), Some(TxHeight::Confirmed(0)))]
+        })
+    );
+}
+
+#[test]
+fn invalidate_first_and_only_checkpoint_without_tx_changes() {
+    let chain1 = chain!(checkpoints: [[0,h!("A")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    let chain2 = chain!(checkpoints: [[0,h!("A'")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [(0, Some(h!("A'")))],
+            txids: []
+        },)
+    );
+}
+
+#[test]
+fn invalidate_first_and_only_checkpoint_with_tx_move_forward() {
+    let chain1 = chain!(checkpoints: [[0,h!("A")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    let chain2 = chain!(checkpoints: [[0,h!("A'")],[1, h!("B")]], txids: [(h!("tx0"), TxHeight::Confirmed(1))]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [(0, Some(h!("A'"))), (1, Some(h!("B")))],
+            txids: [(h!("tx0"), Some(TxHeight::Confirmed(1)))]
+        },)
+    );
+}
+
+#[test]
+fn invalidate_first_and_only_checkpoint_with_tx_move_backward() {
+    let chain1 = chain!(checkpoints: [[1,h!("B")]], txids: [(h!("tx0"), TxHeight::Confirmed(1))]);
+    let chain2 = chain!(checkpoints: [[0,h!("A")],[1, h!("B'")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [(0, Some(h!("A"))), (1, Some(h!("B'")))],
+            txids: [(h!("tx0"), Some(TxHeight::Confirmed(0)))]
+        },)
+    );
+}
+
+#[test]
+fn invalidate_a_checkpoint_and_try_and_move_tx_when_it_wasnt_within_invalidation() {
+    let chain1 = chain!(checkpoints: [[0, h!("A")], [1, h!("B")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    let chain2 = chain!(checkpoints: [[0, h!("A")], [1, h!("B'")]], txids: [(h!("tx0"), TxHeight::Confirmed(1))]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Err(UpdateError::TxInconsistent {
+            txid: h!("tx0"),
+            original_pos: TxHeight::Confirmed(0),
+            update_pos: TxHeight::Confirmed(1),
+        })
+    );
+}
+
+/// This test doesn't make much sense. We're invalidating a block at height 1 and moving it to
+/// height 0. It should be impossible for it to be at height 1 at any point if it was at height 0
+/// all along.
+#[test]
+fn move_invalidated_tx_into_earlier_checkpoint() {
+    let chain1 = chain!(checkpoints: [[0, h!("A")], [1, h!("B")]], txids: [(h!("tx0"), TxHeight::Confirmed(1))]);
+    let chain2 = chain!(checkpoints: [[0, h!("A")], [1, h!("B'")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [(1, Some(h!("B'")))],
+            txids: [(h!("tx0"), Some(TxHeight::Confirmed(0)))]
+        },)
+    );
+}
+
+#[test]
+fn invalidate_first_and_only_checkpoint_with_tx_move_to_mempool() {
+    let chain1 = chain!(checkpoints: [[0,h!("A")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    let chain2 = chain!(checkpoints: [[0,h!("A'")]], txids: [(h!("tx0"), TxHeight::Unconfirmed)]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [(0, Some(h!("A'")))],
+            txids: [(h!("tx0"), Some(TxHeight::Unconfirmed))]
+        },)
+    );
+}
+
+#[test]
+fn confirm_tx_without_extending_chain() {
+    let chain1 = chain!(checkpoints: [[0,h!("A")]], txids: [(h!("tx0"), TxHeight::Unconfirmed)]);
+    let chain2 = chain!(checkpoints: [[0,h!("A")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [],
+            txids: [(h!("tx0"), Some(TxHeight::Confirmed(0)))]
+        },)
+    );
+}
+
+#[test]
+fn confirm_tx_backwards_while_extending_chain() {
+    let chain1 = chain!(checkpoints: [[0,h!("A")]], txids: [(h!("tx0"), TxHeight::Unconfirmed)]);
+    let chain2 = chain!(checkpoints: [[0,h!("A")],[1,h!("B")]], txids: [(h!("tx0"), TxHeight::Confirmed(0))]);
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [(1, Some(h!("B")))],
+            txids: [(h!("tx0"), Some(TxHeight::Confirmed(0)))]
+        },)
+    );
+}
+
+#[test]
+fn confirm_tx_in_new_block() {
+    let chain1 = chain!(checkpoints: [[0,h!("A")]], txids: [(h!("tx0"), TxHeight::Unconfirmed)]);
+    let chain2 = chain! {
+        checkpoints: [[0,h!("A")], [1,h!("B")]],
+        txids: [(h!("tx0"), TxHeight::Confirmed(1))]
+    };
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [(1, Some(h!("B")))],
+            txids: [(h!("tx0"), Some(TxHeight::Confirmed(1)))]
+        },)
+    );
+}
+
+#[test]
+fn merging_mempool_of_empty_chains_doesnt_fail() {
+    let chain1 = chain!(checkpoints: [], txids: [(h!("tx0"), TxHeight::Unconfirmed)]);
+    let chain2 = chain!(checkpoints: [], txids: [(h!("tx1"), TxHeight::Unconfirmed)]);
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [],
+            txids: [(h!("tx1"), Some(TxHeight::Unconfirmed))]
+        },)
+    );
+}
+
+#[test]
+fn cannot_insert_confirmed_tx_without_checkpoints() {
+    let chain = SparseChain::default();
+    assert_eq!(
+        chain.insert_tx_preview(h!("A"), TxHeight::Confirmed(0)),
+        Err(InsertTxError::TxTooHigh {
+            txid: h!("A"),
+            tx_height: 0,
+            tip_height: None
+        })
+    );
+}
+
+#[test]
+fn empty_chain_can_add_unconfirmed_transactions() {
+    let chain1 = chain!(checkpoints: [[0, h!("A")]], txids: []);
+    let chain2 = chain!(checkpoints: [], txids: [(h!("tx0"), TxHeight::Unconfirmed)]);
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [],
+            txids: [ (h!("tx0"), Some(TxHeight::Unconfirmed)) ]
+        },)
+    );
+}
+
+#[test]
+fn can_update_with_shorter_chain() {
+    let chain1 = chain!(checkpoints: [[1, h!("B")],[2, h!("C")]], txids: []);
+    let chain2 = chain!(checkpoints: [[1, h!("B")]], txids: [(h!("tx0"), TxHeight::Confirmed(1))]);
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [],
+            txids: [(h!("tx0"), Some(TxHeight::Confirmed(1)))]
+        },)
+    )
+}
+
+#[test]
+fn can_introduce_older_checkpoints() {
+    let chain1 = chain!(checkpoints: [[2, h!("C")], [3, h!("D")]], txids: []);
+    let chain2 = chain!(checkpoints: [[1, h!("B")], [2, h!("C")]], txids: []);
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [(1, Some(h!("B")))],
+            txids: []
+        },)
+    );
+}
+
+#[test]
+fn fix_blockhash_before_agreement_point() {
+    let chain1 = chain!([0, h!("im-wrong")], [1, h!("we-agree")]);
+    let chain2 = chain!([0, h!("fix")], [1, h!("we-agree")]);
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [(0, Some(h!("fix")))],
+            txids: []
+        },)
+    )
+}
+
+// TODO: Use macro
+#[test]
+fn cannot_change_ext_index_of_confirmed_tx() {
+    let chain1 = chain!(
+        index: TestIndex,
+        checkpoints: [[1, h!("A")]],
+        txids: [(h!("tx0"), TestIndex(TxHeight::Confirmed(1), 10))]
+    );
+    let chain2 = chain!(
+        index: TestIndex,
+        checkpoints: [[1, h!("A")]],
+        txids: [(h!("tx0"), TestIndex(TxHeight::Confirmed(1), 20))]
+    );
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Err(UpdateError::TxInconsistent {
+            txid: h!("tx0"),
+            original_pos: TestIndex(TxHeight::Confirmed(1), 10),
+            update_pos: TestIndex(TxHeight::Confirmed(1), 20),
+        }),
+    )
+}
+
+#[test]
+fn can_change_index_of_unconfirmed_tx() {
+    let chain1 = chain!(
+        index: TestIndex,
+        checkpoints: [[1, h!("A")]],
+        txids: [(h!("tx1"), TestIndex(TxHeight::Unconfirmed, 10))]
+    );
+    let chain2 = chain!(
+        index: TestIndex,
+        checkpoints: [[1, h!("A")]],
+        txids: [(h!("tx1"), TestIndex(TxHeight::Unconfirmed, 20))]
+    );
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(ChangeSet {
+            checkpoints: [].into(),
+            txids: [(h!("tx1"), Some(TestIndex(TxHeight::Unconfirmed, 20)),)].into()
+        },),
+    )
+}
+
+/// B and C are in both chain and update
+/// ```
+///        | 0 | 1 | 2 | 3 | 4
+/// chain  |     B   C
+/// update | A   B   C   D
+/// ```
+/// This should succeed with the point of agreement being C and A should be added in addition.
+#[test]
+fn two_points_of_agreement() {
+    let chain1 = chain!([1, h!("B")], [2, h!("C")]);
+    let chain2 = chain!([0, h!("A")], [1, h!("B")], [2, h!("C")], [3, h!("D")]);
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [(0, Some(h!("A"))), (3, Some(h!("D")))]
+        },),
+    );
+}
+
+/// Update and chain does not connect:
+/// ```
+///        | 0 | 1 | 2 | 3 | 4
+/// chain  |     B   C
+/// update | A   B       D
+/// ```
+/// This should fail as we cannot figure out whether C & D are on the same chain
+#[test]
+fn update_and_chain_does_not_connect() {
+    let chain1 = chain!([1, h!("B")], [2, h!("C")]);
+    let chain2 = chain!([0, h!("A")], [1, h!("B")], [3, h!("D")]);
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Err(UpdateError::NotConnected(2)),
+    );
+}
+
+/// Transient invalidation:
+/// ```
+///        | 0 | 1 | 2 | 3 | 4 | 5
+/// chain  | A       B   C       E
+/// update | A       B'  C'  D
+/// ```
+/// This should succeed and invalidate B,C and E with point of agreement being A.
+/// It should also invalidate transactions at height 1.
+#[test]
+fn transitive_invalidation_applies_to_checkpoints_higher_than_invalidation() {
+    let chain1 = chain! {
+        checkpoints: [[0, h!("A")], [2, h!("B")], [3, h!("C")], [5, h!("E")]],
+        txids: [
+            (h!("a"), TxHeight::Confirmed(0)),
+            (h!("b1"), TxHeight::Confirmed(1)),
+            (h!("b2"), TxHeight::Confirmed(2)),
+            (h!("d"), TxHeight::Confirmed(3)),
+            (h!("e"), TxHeight::Confirmed(5))
+        ]
+    };
+    let chain2 = chain! {
+        checkpoints: [[0, h!("A")], [2, h!("B'")], [3, h!("C'")], [4, h!("D")]],
+        txids: [(h!("b1"), TxHeight::Confirmed(4)), (h!("b2"), TxHeight::Confirmed(3))]
+    };
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [
+                (2, Some(h!("B'"))),
+                (3, Some(h!("C'"))),
+                (4, Some(h!("D"))),
+                (5, None)
+            ],
+            txids: [
+                (h!("b1"), Some(TxHeight::Confirmed(4))),
+                (h!("b2"), Some(TxHeight::Confirmed(3))),
+                (h!("d"), Some(TxHeight::Unconfirmed)),
+                (h!("e"), Some(TxHeight::Unconfirmed))
+            ]
+        },)
+    );
+}
+
+/// Transient invalidation:
+/// ```
+///        | 0 | 1 | 2 | 3 | 4
+/// chain  |     B   C       E
+/// update |     B'  C'  D
+/// ```
+///
+/// This should succeed and invalidate B, C and E with no point of agreement
+#[test]
+fn transitive_invalidation_applies_to_checkpoints_higher_than_invalidation_no_point_of_agreement() {
+    let chain1 = chain!([1, h!("B")], [2, h!("C")], [4, h!("E")]);
+    let chain2 = chain!([1, h!("B'")], [2, h!("C'")], [3, h!("D")]);
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [
+                (1, Some(h!("B'"))),
+                (2, Some(h!("C'"))),
+                (3, Some(h!("D"))),
+                (4, None)
+            ]
+        },)
+    )
+}
+
+/// Transient invalidation:
+/// ```
+///        | 0 | 1 | 2 | 3 | 4
+/// chain  | A   B   C       E
+/// update |     B'  C'  D
+/// ```
+///
+/// This should fail since although it tells us that B and C are invalid it doesn't tell us whether
+/// A was invalid.
+#[test]
+fn invalidation_but_no_connection() {
+    let chain1 = chain!([0, h!("A")], [1, h!("B")], [2, h!("C")], [4, h!("E")]);
+    let chain2 = chain!([1, h!("B'")], [2, h!("C'")], [3, h!("D")]);
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Err(UpdateError::NotConnected(0))
+    )
+}
+
+#[test]
+fn checkpoint_limit_is_respected() {
+    let mut chain1 = SparseChain::default();
+    let _ = chain1
+        .apply_update(chain!(
+            [1, h!("A")],
+            [2, h!("B")],
+            [3, h!("C")],
+            [4, h!("D")],
+            [5, h!("E")]
+        ))
+        .unwrap();
+
+    assert_eq!(chain1.checkpoints().len(), 5);
+    chain1.set_checkpoint_limit(Some(4));
+    assert_eq!(chain1.checkpoints().len(), 4);
+
+    let _ = chain1
+        .insert_checkpoint(BlockId {
+            height: 6,
+            hash: h!("F"),
+        })
+        .unwrap();
+    assert_eq!(chain1.checkpoints().len(), 4);
+
+    let changeset = chain1.determine_changeset(&chain!([6, h!("F")], [7, h!("G")]));
+    assert_eq!(changeset, Ok(changeset!(checkpoints: [(7, Some(h!("G")))])));
+
+    chain1.apply_changeset(changeset.unwrap());
+
+    assert_eq!(chain1.checkpoints().len(), 4);
+}
+
+#[test]
+fn range_txids_by_height() {
+    let mut chain = chain!(index: TestIndex, checkpoints: [[1, h!("block 1")], [2, h!("block 2")]]);
+
+    let txids: [(TestIndex, Txid); 4] = [
+        (
+            TestIndex(TxHeight::Confirmed(1), u32::MIN),
+            Txid::from_inner([0x00; 32]),
+        ),
+        (
+            TestIndex(TxHeight::Confirmed(1), u32::MAX),
+            Txid::from_inner([0xfe; 32]),
+        ),
+        (
+            TestIndex(TxHeight::Confirmed(2), u32::MIN),
+            Txid::from_inner([0x01; 32]),
+        ),
+        (
+            TestIndex(TxHeight::Confirmed(2), u32::MAX),
+            Txid::from_inner([0xff; 32]),
+        ),
+    ];
+
+    // populate chain with txids
+    for (index, txid) in txids {
+        let _ = chain.insert_tx(txid, index).expect("should succeed");
+    }
+
+    // inclusive start
+    assert_eq!(
+        chain
+            .range_txids_by_height(TxHeight::Confirmed(1)..)
+            .collect::<Vec<_>>(),
+        txids.iter().collect::<Vec<_>>(),
+    );
+
+    // exclusive start
+    assert_eq!(
+        chain
+            .range_txids_by_height((Bound::Excluded(TxHeight::Confirmed(1)), Bound::Unbounded,))
+            .collect::<Vec<_>>(),
+        txids[2..].iter().collect::<Vec<_>>(),
+    );
+
+    // inclusive end
+    assert_eq!(
+        chain
+            .range_txids_by_height((Bound::Unbounded, Bound::Included(TxHeight::Confirmed(2))))
+            .collect::<Vec<_>>(),
+        txids[..4].iter().collect::<Vec<_>>(),
+    );
+
+    // exclusive end
+    assert_eq!(
+        chain
+            .range_txids_by_height(..TxHeight::Confirmed(2))
+            .collect::<Vec<_>>(),
+        txids[..2].iter().collect::<Vec<_>>(),
+    );
+}
+
+#[test]
+fn range_txids_by_index() {
+    let mut chain = chain!(index: TestIndex, checkpoints: [[1, h!("block 1")],[2, h!("block 2")]]);
+
+    let txids: [(TestIndex, Txid); 4] = [
+        (TestIndex(TxHeight::Confirmed(1), u32::MIN), h!("tx 1 min")),
+        (TestIndex(TxHeight::Confirmed(1), u32::MAX), h!("tx 1 max")),
+        (TestIndex(TxHeight::Confirmed(2), u32::MIN), h!("tx 2 min")),
+        (TestIndex(TxHeight::Confirmed(2), u32::MAX), h!("tx 2 max")),
+    ];
+
+    // populate chain with txids
+    for (index, txid) in txids {
+        let _ = chain.insert_tx(txid, index).expect("should succeed");
+    }
+
+    // inclusive start
+    assert_eq!(
+        chain
+            .range_txids_by_position(TestIndex(TxHeight::Confirmed(1), u32::MIN)..)
+            .collect::<Vec<_>>(),
+        txids.iter().collect::<Vec<_>>(),
+    );
+    assert_eq!(
+        chain
+            .range_txids_by_position(TestIndex(TxHeight::Confirmed(1), u32::MAX)..)
+            .collect::<Vec<_>>(),
+        txids[1..].iter().collect::<Vec<_>>(),
+    );
+
+    // exclusive start
+    assert_eq!(
+        chain
+            .range_txids_by_position((
+                Bound::Excluded(TestIndex(TxHeight::Confirmed(1), u32::MIN)),
+                Bound::Unbounded
+            ))
+            .collect::<Vec<_>>(),
+        txids[1..].iter().collect::<Vec<_>>(),
+    );
+    assert_eq!(
+        chain
+            .range_txids_by_position((
+                Bound::Excluded(TestIndex(TxHeight::Confirmed(1), u32::MAX)),
+                Bound::Unbounded
+            ))
+            .collect::<Vec<_>>(),
+        txids[2..].iter().collect::<Vec<_>>(),
+    );
+
+    // inclusive end
+    assert_eq!(
+        chain
+            .range_txids_by_position((
+                Bound::Unbounded,
+                Bound::Included(TestIndex(TxHeight::Confirmed(2), u32::MIN))
+            ))
+            .collect::<Vec<_>>(),
+        txids[..3].iter().collect::<Vec<_>>(),
+    );
+    assert_eq!(
+        chain
+            .range_txids_by_position((
+                Bound::Unbounded,
+                Bound::Included(TestIndex(TxHeight::Confirmed(2), u32::MAX))
+            ))
+            .collect::<Vec<_>>(),
+        txids[..4].iter().collect::<Vec<_>>(),
+    );
+
+    // exclusive end
+    assert_eq!(
+        chain
+            .range_txids_by_position(..TestIndex(TxHeight::Confirmed(2), u32::MIN))
+            .collect::<Vec<_>>(),
+        txids[..2].iter().collect::<Vec<_>>(),
+    );
+    assert_eq!(
+        chain
+            .range_txids_by_position(..TestIndex(TxHeight::Confirmed(2), u32::MAX))
+            .collect::<Vec<_>>(),
+        txids[..3].iter().collect::<Vec<_>>(),
+    );
+}
+
+#[test]
+fn range_txids() {
+    let mut chain = SparseChain::default();
+
+    let txids = (0..100)
+        .map(|v| Txid::hash(v.to_string().as_bytes()))
+        .collect::<BTreeSet<Txid>>();
+
+    // populate chain
+    for txid in &txids {
+        let _ = chain
+            .insert_tx(*txid, TxHeight::Unconfirmed)
+            .expect("should succeed");
+    }
+
+    for txid in &txids {
+        assert_eq!(
+            chain
+                .range_txids((TxHeight::Unconfirmed, *txid)..)
+                .map(|(_, txid)| txid)
+                .collect::<Vec<_>>(),
+            txids.range(*txid..).collect::<Vec<_>>(),
+            "range with inclusive start should succeed"
+        );
+
+        assert_eq!(
+            chain
+                .range_txids((
+                    Bound::Excluded((TxHeight::Unconfirmed, *txid)),
+                    Bound::Unbounded,
+                ))
+                .map(|(_, txid)| txid)
+                .collect::<Vec<_>>(),
+            txids
+                .range((Bound::Excluded(*txid), Bound::Unbounded,))
+                .collect::<Vec<_>>(),
+            "range with exclusive start should succeed"
+        );
+
+        assert_eq!(
+            chain
+                .range_txids(..(TxHeight::Unconfirmed, *txid))
+                .map(|(_, txid)| txid)
+                .collect::<Vec<_>>(),
+            txids.range(..*txid).collect::<Vec<_>>(),
+            "range with exclusive end should succeed"
+        );
+
+        assert_eq!(
+            chain
+                .range_txids((
+                    Bound::Included((TxHeight::Unconfirmed, *txid)),
+                    Bound::Unbounded,
+                ))
+                .map(|(_, txid)| txid)
+                .collect::<Vec<_>>(),
+            txids
+                .range((Bound::Included(*txid), Bound::Unbounded,))
+                .collect::<Vec<_>>(),
+            "range with inclusive end should succeed"
+        );
+    }
+}
+
+#[test]
+fn invalidated_txs_move_to_unconfirmed() {
+    let chain1 = chain! {
+        checkpoints: [[0, h!("A")], [1, h!("B")], [2, h!("C")]],
+        txids: [
+            (h!("a"), TxHeight::Confirmed(0)),
+            (h!("b"), TxHeight::Confirmed(1)),
+            (h!("c"), TxHeight::Confirmed(2)),
+            (h!("d"), TxHeight::Unconfirmed)
+        ]
+    };
+
+    let chain2 = chain!([0, h!("A")], [1, h!("B'")]);
+
+    assert_eq!(
+        chain1.determine_changeset(&chain2),
+        Ok(changeset! {
+            checkpoints: [
+                (1, Some(h!("B'"))),
+                (2, None)
+            ],
+            txids: [
+                (h!("b"), Some(TxHeight::Unconfirmed)),
+                (h!("c"), Some(TxHeight::Unconfirmed))
+            ]
+        },)
+    );
+}
+
+#[test]
+fn change_tx_position_from_unconfirmed_to_confirmed() {
+    let mut chain = SparseChain::<TxHeight>::default();
+    let txid = h!("txid");
+
+    let _ = chain.insert_tx(txid, TxHeight::Unconfirmed).unwrap();
+
+    assert_eq!(chain.tx_position(txid), Some(&TxHeight::Unconfirmed));
+    let _ = chain
+        .insert_checkpoint(BlockId {
+            height: 0,
+            hash: h!("0"),
+        })
+        .unwrap();
+    let _ = chain.insert_tx(txid, TxHeight::Confirmed(0)).unwrap();
+
+    assert_eq!(chain.tx_position(txid), Some(&TxHeight::Confirmed(0)));
+}
--- a/crates/chain/tests/test_tx_graph.rs
+++ b/crates/chain/tests/test_tx_graph.rs
@@ -2,19 +2,13 @@
 mod common;
 use bdk_chain::{
    collections::*,
-    local_chain::LocalChain,
    tx_graph::{Additions, TxGraph},
-    Append, BlockId, ChainPosition, ConfirmationHeightAnchor,
-};
-use bitcoin::{
-    hashes::Hash, BlockHash, OutPoint, PackedLockTime, Script, Transaction, TxIn, TxOut, Txid,
 };
+use bitcoin::{hashes::Hash, OutPoint, PackedLockTime, Script, Transaction, TxIn, TxOut, Txid};
 use core::iter;
-use std::vec;

 #[test]
 fn insert_txouts() {
-    // 2 (Outpoint, TxOut) tupples that denotes original data in the graph, as partial transactions.
    let original_ops = [
        (
            OutPoint::new(h!("tx1"), 1),
@@ -32,7 +26,6 @@ fn insert_txouts() {
        ),
    ];

-    // Another (OutPoint, TxOut) tupple to be used as update as partial transaction.
    let update_ops = [(
        OutPoint::new(h!("tx2"), 0),
        TxOut {
@@ -41,37 +34,13 @@ fn insert_txouts() {
        },
    )];

-    // One full transaction to be included in the update
-    let update_txs = Transaction {
-        version: 0x01,
-        lock_time: PackedLockTime(0),
-        input: vec![TxIn {
-            previous_output: OutPoint::null(),
-            ..Default::default()
-        }],
-        output: vec![TxOut {
-            value: 30_000,
-            script_pubkey: Script::new(),
-        }],
-    };
-
-    // Conf anchor used to mark the full transaction as confirmed.
-    let conf_anchor = ChainPosition::Confirmed(BlockId {
-        height: 100,
-        hash: h!("random blockhash"),
-    });
-
-    // Unconfirmed anchor to mark the partial transactions as unconfirmed
-    let unconf_anchor = ChainPosition::<BlockId>::Unconfirmed(1000000);
-
-    // Make the original graph
    let mut graph = {
-        let mut graph = TxGraph::<ChainPosition<BlockId>>::default();
+        let mut graph = TxGraph::default();
        for (outpoint, txout) in &original_ops {
            assert_eq!(
                graph.insert_txout(*outpoint, txout.clone()),
                Additions {
-                    txouts: [(*outpoint, txout.clone())].into(),
+                    txout: [(*outpoint, txout.clone())].into(),
                    ..Default::default()
                }
            );
@@ -79,113 +48,34 @@ fn insert_txouts() {
        graph
    };

-    // Make the update graph
    let update = {
        let mut graph = TxGraph::default();
        for (outpoint, txout) in &update_ops {
-            // Insert partials transactions
            assert_eq!(
                graph.insert_txout(*outpoint, txout.clone()),
                Additions {
-                    txouts: [(*outpoint, txout.clone())].into(),
+                    txout: [(*outpoint, txout.clone())].into(),
                    ..Default::default()
                }
            );
-            // Mark them unconfirmed.
-            assert_eq!(
-                graph.insert_anchor(outpoint.txid, unconf_anchor),
-                Additions {
-                    txs: [].into(),
-                    txouts: [].into(),
-                    anchors: [(unconf_anchor, outpoint.txid)].into(),
-                    last_seen: [].into()
-                }
-            );
-            // Mark them last seen at.
-            assert_eq!(
-                graph.insert_seen_at(outpoint.txid, 1000000),
-                Additions {
-                    txs: [].into(),
-                    txouts: [].into(),
-                    anchors: [].into(),
-                    last_seen: [(outpoint.txid, 1000000)].into()
-                }
-            );
        }
-        // Insert the full transaction
-        assert_eq!(
-            graph.insert_tx(update_txs.clone()),
-            Additions {
-                txs: [update_txs.clone()].into(),
-                ..Default::default()
-            }
-        );
-
-        // Mark it as confirmed.
-        assert_eq!(
-            graph.insert_anchor(update_txs.txid(), conf_anchor),
-            Additions {
-                txs: [].into(),
-                txouts: [].into(),
-                anchors: [(conf_anchor, update_txs.txid())].into(),
-                last_seen: [].into()
-            }
-        );
        graph
    };

-    // Check the resulting addition.
    let additions = graph.determine_additions(&update);

    assert_eq!(
        additions,
        Additions {
-            txs: [update_txs.clone()].into(),
-            txouts: update_ops.into(),
-            anchors: [(conf_anchor, update_txs.txid()), (unconf_anchor, h!("tx2"))].into(),
-            last_seen: [(h!("tx2"), 1000000)].into()
+            tx: [].into(),
+            txout: update_ops.into(),
        }
    );

-    // Apply addition and check the new graph counts.
    graph.apply_additions(additions);
-    assert_eq!(graph.all_txouts().count(), 4);
-    assert_eq!(graph.full_txs().count(), 1);
-    assert_eq!(graph.floating_txouts().count(), 3);
-
-    // Check TxOuts are fetched correctly from the graph.
-    assert_eq!(
-        graph.tx_outputs(h!("tx1")).expect("should exists"),
-        [
-            (
-                1u32,
-                &TxOut {
-                    value: 10_000,
-                    script_pubkey: Script::new(),
-                }
-            ),
-            (
-                2u32,
-                &TxOut {
-                    value: 20_000,
-                    script_pubkey: Script::new(),
-                }
-            )
-        ]
-        .into()
-    );
-
-    assert_eq!(
-        graph.tx_outputs(update_txs.txid()).expect("should exists"),
-        [(
-            0u32,
-            &TxOut {
-                value: 30_000,
-                script_pubkey: Script::new()
-            }
-        )]
-        .into()
-    );
+    assert_eq!(graph.all_txouts().count(), 3);
+    assert_eq!(graph.full_transactions().count(), 0);
+    assert_eq!(graph.partial_transactions().count(), 2);
 }

 #[test]
@@ -200,10 +90,10 @@ fn insert_tx_graph_doesnt_count_coinbase_as_spent() {
        output: vec![],
    };

-    let mut graph = TxGraph::<()>::default();
+    let mut graph = TxGraph::default();
    let _ = graph.insert_tx(tx);
    assert!(graph.outspends(OutPoint::null()).is_empty());
-    assert!(graph.tx_spends(Txid::all_zeros()).next().is_none());
+    assert!(graph.tx_outspends(Txid::all_zeros()).next().is_none());
 }

 #[test]
@@ -230,8 +120,8 @@ fn insert_tx_graph_keeps_track_of_spend() {
        output: vec![],
    };

-    let mut graph1 = TxGraph::<()>::default();
-    let mut graph2 = TxGraph::<()>::default();
+    let mut graph1 = TxGraph::default();
+    let mut graph2 = TxGraph::default();

    // insert in different order
    let _ = graph1.insert_tx(tx1.clone());
@@ -259,14 +149,14 @@ fn insert_tx_can_retrieve_full_tx_from_graph() {
        output: vec![TxOut::default()],
    };

-    let mut graph = TxGraph::<()>::default();
+    let mut graph = TxGraph::default();
    let _ = graph.insert_tx(tx.clone());
    assert_eq!(graph.get_tx(tx.txid()), Some(&tx));
 }

 #[test]
 fn insert_tx_displaces_txouts() {
-    let mut tx_graph = TxGraph::<()>::default();
+    let mut tx_graph = TxGraph::default();
    let tx = Transaction {
        version: 0x01,
        lock_time: PackedLockTime(0),
@@ -322,7 +212,7 @@ fn insert_tx_displaces_txouts() {

 #[test]
 fn insert_txout_does_not_displace_tx() {
-    let mut tx_graph = TxGraph::<()>::default();
+    let mut tx_graph = TxGraph::default();
    let tx = Transaction {
        version: 0x01,
        lock_time: PackedLockTime(0),
@@ -378,7 +268,7 @@ fn insert_txout_does_not_displace_tx() {

 #[test]
 fn test_calculate_fee() {
-    let mut graph = TxGraph::<()>::default();
+    let mut graph = TxGraph::default();
    let intx1 = Transaction {
        version: 0x01,
        lock_time: PackedLockTime(0),
@@ -472,7 +362,7 @@ fn test_calculate_fee_on_coinbase() {
        output: vec![TxOut::default()],
    };

-    let graph = TxGraph::<()>::default();
+    let graph = TxGraph::default();

    assert_eq!(graph.calculate_fee(&tx), Some(0));
 }
@@ -514,7 +404,7 @@ fn test_conflicting_descendants() {
    let txid_a = tx_a.txid();
    let txid_b = tx_b.txid();

-    let mut graph = TxGraph::<()>::default();
+    let mut graph = TxGraph::default();
    let _ = graph.insert_tx(tx_a);
    let _ = graph.insert_tx(tx_b);

@@ -590,7 +480,7 @@ fn test_descendants_no_repeat() {
        })
        .collect::<Vec<_>>();

-    let mut graph = TxGraph::<()>::default();
+    let mut graph = TxGraph::default();
    let mut expected_txids = BTreeSet::new();

    // these are NOT descendants of `tx_a`
@@ -620,205 +510,3 @@ fn test_descendants_no_repeat() {
    }
    assert!(expected_txids.is_empty());
 }
-
-#[test]
-fn test_chain_spends() {
-    let local_chain: LocalChain = (0..=100)
-        .map(|ht| (ht, BlockHash::hash(format!("Block Hash {}", ht).as_bytes())))
-        .collect::<BTreeMap<u32, BlockHash>>()
-        .into();
-    let tip = local_chain.tip().expect("must have tip");
-
-    // The parent tx contains 2 outputs. Which are spent by one confirmed and one unconfirmed tx.
-    // The parent tx is confirmed at block 95.
-    let tx_0 = Transaction {
-        input: vec![],
-        output: vec![
-            TxOut {
-                value: 10_000,
-                script_pubkey: Script::new(),
-            },
-            TxOut {
-                value: 20_000,
-                script_pubkey: Script::new(),
-            },
-        ],
-        ..common::new_tx(0)
-    };
-
-    // The first confirmed transaction spends vout: 0. And is confirmed at block 98.
-    let tx_1 = Transaction {
-        input: vec![TxIn {
-            previous_output: OutPoint::new(tx_0.txid(), 0),
-            ..TxIn::default()
-        }],
-        output: vec![
-            TxOut {
-                value: 5_000,
-                script_pubkey: Script::new(),
-            },
-            TxOut {
-                value: 5_000,
-                script_pubkey: Script::new(),
-            },
-        ],
-        ..common::new_tx(0)
-    };
-
-    // The second transactions spends vout:1, and is unconfirmed.
-    let tx_2 = Transaction {
-        input: vec![TxIn {
-            previous_output: OutPoint::new(tx_0.txid(), 1),
-            ..TxIn::default()
-        }],
-        output: vec![
-            TxOut {
-                value: 10_000,
-                script_pubkey: Script::new(),
-            },
-            TxOut {
-                value: 10_000,
-                script_pubkey: Script::new(),
-            },
-        ],
-        ..common::new_tx(0)
-    };
-
-    let mut graph = TxGraph::<ConfirmationHeightAnchor>::default();
-
-    let _ = graph.insert_tx(tx_0.clone());
-    let _ = graph.insert_tx(tx_1.clone());
-    let _ = graph.insert_tx(tx_2.clone());
-
-    [95, 98]
-        .iter()
-        .zip([&tx_0, &tx_1].into_iter())
-        .for_each(|(ht, tx)| {
-            let _ = graph.insert_anchor(
-                tx.txid(),
-                ConfirmationHeightAnchor {
-                    anchor_block: tip,
-                    confirmation_height: *ht,
-                },
-            );
-        });
-
-    // Assert that confirmed spends are returned correctly.
-    assert_eq!(
-        graph.get_chain_spend(&local_chain, tip, OutPoint::new(tx_0.txid(), 0)),
-        Some((
-            ChainPosition::Confirmed(&ConfirmationHeightAnchor {
-                anchor_block: tip,
-                confirmation_height: 98
-            }),
-            tx_1.txid(),
-        )),
-    );
-
-    // Check if chain position is returned correctly.
-    assert_eq!(
-        graph.get_chain_position(&local_chain, tip, tx_0.txid()),
-        // Some(ObservedAs::Confirmed(&local_chain.get_block(95).expect("block expected"))),
-        Some(ChainPosition::Confirmed(&ConfirmationHeightAnchor {
-            anchor_block: tip,
-            confirmation_height: 95
-        }))
-    );
-
-    // Even if unconfirmed tx has a last_seen of 0, it can still be part of a chain spend.
-    assert_eq!(
-        graph.get_chain_spend(&local_chain, tip, OutPoint::new(tx_0.txid(), 1)),
-        Some((ChainPosition::Unconfirmed(0), tx_2.txid())),
-    );
-
-    // Mark the unconfirmed as seen and check correct ObservedAs status is returned.
-    let _ = graph.insert_seen_at(tx_2.txid(), 1234567);
-
-    // Check chain spend returned correctly.
-    assert_eq!(
-        graph
-            .get_chain_spend(&local_chain, tip, OutPoint::new(tx_0.txid(), 1))
-            .unwrap(),
-        (ChainPosition::Unconfirmed(1234567), tx_2.txid())
-    );
-
-    // A conflicting transaction that conflicts with tx_1.
-    let tx_1_conflict = Transaction {
-        input: vec![TxIn {
-            previous_output: OutPoint::new(tx_0.txid(), 0),
-            ..Default::default()
-        }],
-        ..common::new_tx(0)
-    };
-    let _ = graph.insert_tx(tx_1_conflict.clone());
-
-    // Because this tx conflicts with an already confirmed transaction, chain position should return none.
-    assert!(graph
-        .get_chain_position(&local_chain, tip, tx_1_conflict.txid())
-        .is_none());
-
-    // Another conflicting tx that conflicts with tx_2.
-    let tx_2_conflict = Transaction {
-        input: vec![TxIn {
-            previous_output: OutPoint::new(tx_0.txid(), 1),
-            ..Default::default()
-        }],
-        ..common::new_tx(0)
-    };
-
-    // Insert in graph and mark it as seen.
-    let _ = graph.insert_tx(tx_2_conflict.clone());
-    let _ = graph.insert_seen_at(tx_2_conflict.txid(), 1234568);
-
-    // This should return a valid observation with correct last seen.
-    assert_eq!(
-        graph
-            .get_chain_position(&local_chain, tip, tx_2_conflict.txid())
-            .expect("position expected"),
-        ChainPosition::Unconfirmed(1234568)
-    );
-
-    // Chain_spend now catches the new transaction as the spend.
-    assert_eq!(
-        graph
-            .get_chain_spend(&local_chain, tip, OutPoint::new(tx_0.txid(), 1))
-            .expect("expect observation"),
-        (ChainPosition::Unconfirmed(1234568), tx_2_conflict.txid())
-    );
-
-    // Chain position of the `tx_2` is now none, as it is older than `tx_2_conflict`
-    assert!(graph
-        .get_chain_position(&local_chain, tip, tx_2.txid())
-        .is_none());
-}
-
-/// Ensure that `last_seen` values only increase during [`Append::append`].
-#[test]
-fn test_additions_last_seen_append() {
-    let txid: Txid = h!("test txid");
-
-    let test_cases: &[(Option<u64>, Option<u64>)] = &[
-        (Some(5), Some(6)),
-        (Some(5), Some(5)),
-        (Some(6), Some(5)),
-        (None, Some(5)),
-        (Some(5), None),
-    ];
-
-    for (original_ls, update_ls) in test_cases {
-        let mut original = Additions::<()> {
-            last_seen: original_ls.map(|ls| (txid, ls)).into_iter().collect(),
-            ..Default::default()
-        };
-        let update = Additions::<()> {
-            last_seen: update_ls.map(|ls| (txid, ls)).into_iter().collect(),
-            ..Default::default()
-        };
-
-        original.append(update);
-        assert_eq!(
-            &original.last_seen.get(&txid).cloned(),
-            Ord::max(original_ls, update_ls),
-        );
-    }
-}
--- a/crates/electrum/Cargo.toml
+++ b/crates/electrum/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "bdk_electrum"
-version = "0.3.0"
+version = "0.2.0"
 edition = "2021"
 homepage = "https://bitcoindevkit.org"
 repository = "https://github.com/bitcoindevkit/bdk"
@@ -12,5 +12,5 @@ readme = "README.md"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

 [dependencies]
-bdk_chain = { path = "../chain", version = "0.5.0", features = ["serde", "miniscript"] }
+bdk_chain = { path = "../chain", version = "0.4.0", features = ["serde", "miniscript"] }
 electrum-client = { version = "0.12" }
--- a/crates/electrum/src/electrum_ext.rs
+++ b/crates/electrum/src/electrum_ext.rs
@@ -1,486 +0,0 @@
-use bdk_chain::{
-    bitcoin::{hashes::hex::FromHex, BlockHash, OutPoint, Script, Transaction, Txid},
-    keychain::LocalUpdate,
-    local_chain::LocalChain,
-    tx_graph::{self, TxGraph},
-    Anchor, BlockId, ConfirmationHeightAnchor, ConfirmationTimeAnchor,
-};
-use electrum_client::{Client, ElectrumApi, Error};
-use std::{
-    collections::{BTreeMap, BTreeSet, HashMap, HashSet},
-    fmt::Debug,
-};
-
-#[derive(Debug, Clone)]
-pub struct ElectrumUpdate<K, A> {
-    pub graph_update: HashMap<Txid, BTreeSet<A>>,
-    pub chain_update: LocalChain,
-    pub keychain_update: BTreeMap<K, u32>,
-}
-
-impl<K, A> Default for ElectrumUpdate<K, A> {
-    fn default() -> Self {
-        Self {
-            graph_update: Default::default(),
-            chain_update: Default::default(),
-            keychain_update: Default::default(),
-        }
-    }
-}
-
-impl<K, A: Anchor> ElectrumUpdate<K, A> {
-    pub fn missing_full_txs<A2>(&self, graph: &TxGraph<A2>) -> Vec<Txid> {
-        self.graph_update
-            .keys()
-            .filter(move |&&txid| graph.as_ref().get_tx(txid).is_none())
-            .cloned()
-            .collect()
-    }
-
-    pub fn finalize(
-        self,
-        client: &Client,
-        seen_at: Option<u64>,
-        missing: Vec<Txid>,
-    ) -> Result<LocalUpdate<K, A>, Error> {
-        let new_txs = client.batch_transaction_get(&missing)?;
-        let mut graph_update = TxGraph::<A>::new(new_txs);
-        for (txid, anchors) in self.graph_update {
-            if let Some(seen_at) = seen_at {
-                let _ = graph_update.insert_seen_at(txid, seen_at);
-            }
-            for anchor in anchors {
-                let _ = graph_update.insert_anchor(txid, anchor);
-            }
-        }
-        Ok(LocalUpdate {
-            keychain: self.keychain_update,
-            graph: graph_update,
-            chain: self.chain_update,
-        })
-    }
-}
-
-impl<K> ElectrumUpdate<K, ConfirmationHeightAnchor> {
-    /// Finalizes the [`ElectrumUpdate`] with `new_txs` and anchors of type
-    /// [`ConfirmationTimeAnchor`].
-    ///
-    /// **Note:** The confirmation time might not be precisely correct if there has been a reorg.
-    /// Electrum's API intends that we use the merkle proof API, we should change `bdk_electrum` to
-    /// use it.
-    pub fn finalize_as_confirmation_time(
-        self,
-        client: &Client,
-        seen_at: Option<u64>,
-        missing: Vec<Txid>,
-    ) -> Result<LocalUpdate<K, ConfirmationTimeAnchor>, Error> {
-        let update = self.finalize(client, seen_at, missing)?;
-
-        let relevant_heights = {
-            let mut visited_heights = HashSet::new();
-            update
-                .graph
-                .all_anchors()
-                .iter()
-                .map(|(a, _)| a.confirmation_height_upper_bound())
-                .filter(move |&h| visited_heights.insert(h))
-                .collect::<Vec<_>>()
-        };
-
-        let height_to_time = relevant_heights
-            .clone()
-            .into_iter()
-            .zip(
-                client
-                    .batch_block_header(relevant_heights)?
-                    .into_iter()
-                    .map(|bh| bh.time as u64),
-            )
-            .collect::<HashMap<u32, u64>>();
-
-        let graph_additions = {
-            let old_additions = TxGraph::default().determine_additions(&update.graph);
-            tx_graph::Additions {
-                txs: old_additions.txs,
-                txouts: old_additions.txouts,
-                last_seen: old_additions.last_seen,
-                anchors: old_additions
-                    .anchors
-                    .into_iter()
-                    .map(|(height_anchor, txid)| {
-                        let confirmation_height = height_anchor.confirmation_height;
-                        let confirmation_time = height_to_time[&confirmation_height];
-                        let time_anchor = ConfirmationTimeAnchor {
-                            anchor_block: height_anchor.anchor_block,
-                            confirmation_height,
-                            confirmation_time,
-                        };
-                        (time_anchor, txid)
-                    })
-                    .collect(),
-            }
-        };
-
-        Ok(LocalUpdate {
-            keychain: update.keychain,
-            graph: {
-                let mut graph = TxGraph::default();
-                graph.apply_additions(graph_additions);
-                graph
-            },
-            chain: update.chain,
-        })
-    }
-}
-
-pub trait ElectrumExt<A> {
-    fn get_tip(&self) -> Result<(u32, BlockHash), Error>;
-
-    fn scan<K: Ord + Clone>(
-        &self,
-        local_chain: &BTreeMap<u32, BlockHash>,
-        keychain_spks: BTreeMap<K, impl IntoIterator<Item = (u32, Script)>>,
-        txids: impl IntoIterator<Item = Txid>,
-        outpoints: impl IntoIterator<Item = OutPoint>,
-        stop_gap: usize,
-        batch_size: usize,
-    ) -> Result<ElectrumUpdate<K, A>, Error>;
-
-    fn scan_without_keychain(
-        &self,
-        local_chain: &BTreeMap<u32, BlockHash>,
-        misc_spks: impl IntoIterator<Item = Script>,
-        txids: impl IntoIterator<Item = Txid>,
-        outpoints: impl IntoIterator<Item = OutPoint>,
-        batch_size: usize,
-    ) -> Result<ElectrumUpdate<(), A>, Error> {
-        let spk_iter = misc_spks
-            .into_iter()
-            .enumerate()
-            .map(|(i, spk)| (i as u32, spk));
-
-        self.scan(
-            local_chain,
-            [((), spk_iter)].into(),
-            txids,
-            outpoints,
-            usize::MAX,
-            batch_size,
-        )
-    }
-}
-
-impl ElectrumExt<ConfirmationHeightAnchor> for Client {
-    fn get_tip(&self) -> Result<(u32, BlockHash), Error> {
-        // TODO: unsubscribe when added to the client, or is there a better call to use here?
-        self.block_headers_subscribe()
-            .map(|data| (data.height as u32, data.header.block_hash()))
-    }
-
-    fn scan<K: Ord + Clone>(
-        &self,
-        local_chain: &BTreeMap<u32, BlockHash>,
-        keychain_spks: BTreeMap<K, impl IntoIterator<Item = (u32, Script)>>,
-        txids: impl IntoIterator<Item = Txid>,
-        outpoints: impl IntoIterator<Item = OutPoint>,
-        stop_gap: usize,
-        batch_size: usize,
-    ) -> Result<ElectrumUpdate<K, ConfirmationHeightAnchor>, Error> {
-        let mut request_spks = keychain_spks
-            .into_iter()
-            .map(|(k, s)| (k, s.into_iter()))
-            .collect::<BTreeMap<K, _>>();
-        let mut scanned_spks = BTreeMap::<(K, u32), (Script, bool)>::new();
-
-        let txids = txids.into_iter().collect::<Vec<_>>();
-        let outpoints = outpoints.into_iter().collect::<Vec<_>>();
-
-        let update = loop {
-            let mut update = ElectrumUpdate::<K, ConfirmationHeightAnchor> {
-                chain_update: prepare_chain_update(self, local_chain)?,
-                ..Default::default()
-            };
-            let anchor_block = update
-                .chain_update
-                .tip()
-                .expect("must have atleast one block");
-
-            if !request_spks.is_empty() {
-                if !scanned_spks.is_empty() {
-                    scanned_spks.append(&mut populate_with_spks(
-                        self,
-                        anchor_block,
-                        &mut update,
-                        &mut scanned_spks
-                            .iter()
-                            .map(|(i, (spk, _))| (i.clone(), spk.clone())),
-                        stop_gap,
-                        batch_size,
-                    )?);
-                }
-                for (keychain, keychain_spks) in &mut request_spks {
-                    scanned_spks.extend(
-                        populate_with_spks(
-                            self,
-                            anchor_block,
-                            &mut update,
-                            keychain_spks,
-                            stop_gap,
-                            batch_size,
-                        )?
-                        .into_iter()
-                        .map(|(spk_i, spk)| ((keychain.clone(), spk_i), spk)),
-                    );
-                }
-            }
-
-            populate_with_txids(self, anchor_block, &mut update, &mut txids.iter().cloned())?;
-
-            let _txs = populate_with_outpoints(
-                self,
-                anchor_block,
-                &mut update,
-                &mut outpoints.iter().cloned(),
-            )?;
-
-            // check for reorgs during scan process
-            let server_blockhash = self
-                .block_header(anchor_block.height as usize)?
-                .block_hash();
-            if anchor_block.hash != server_blockhash {
-                continue; // reorg
-            }
-
-            update.keychain_update = request_spks
-                .into_keys()
-                .filter_map(|k| {
-                    scanned_spks
-                        .range((k.clone(), u32::MIN)..=(k.clone(), u32::MAX))
-                        .rev()
-                        .find(|(_, (_, active))| *active)
-                        .map(|((_, i), _)| (k, *i))
-                })
-                .collect::<BTreeMap<_, _>>();
-            break update;
-        };
-
-        Ok(update)
-    }
-}
-
-/// Prepare an update "template" based on the checkpoints of the `local_chain`.
-fn prepare_chain_update(
-    client: &Client,
-    local_chain: &BTreeMap<u32, BlockHash>,
-) -> Result<LocalChain, Error> {
-    let mut update = LocalChain::default();
-
-    // Find the local chain block that is still there so our update can connect to the local chain.
-    for (&existing_height, &existing_hash) in local_chain.iter().rev() {
-        // TODO: a batch request may be safer, as a reorg that happens when we are obtaining
-        //       `block_header`s will result in inconsistencies
-        let current_hash = client.block_header(existing_height as usize)?.block_hash();
-        let _ = update
-            .insert_block(BlockId {
-                height: existing_height,
-                hash: current_hash,
-            })
-            .expect("This never errors because we are working with a fresh chain");
-
-        if current_hash == existing_hash {
-            break;
-        }
-    }
-
-    // Insert the new tip so new transactions will be accepted into the sparsechain.
-    let tip = {
-        let (height, hash) = crate::get_tip(client)?;
-        BlockId { height, hash }
-    };
-    if update.insert_block(tip).is_err() {
-        // There has been a re-org before we even begin scanning addresses.
-        // Just recursively call (this should never happen).
-        return prepare_chain_update(client, local_chain);
-    }
-
-    Ok(update)
-}
-
-fn determine_tx_anchor(
-    anchor_block: BlockId,
-    raw_height: i32,
-    txid: Txid,
-) -> Option<ConfirmationHeightAnchor> {
-    // The electrum API has a weird quirk where an unconfirmed transaction is presented with a
-    // height of 0. To avoid invalid representation in our data structures, we manually set
-    // transactions residing in the genesis block to have height 0, then interpret a height of 0 as
-    // unconfirmed for all other transactions.
-    if txid
-        == Txid::from_hex("4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b")
-            .expect("must deserialize genesis coinbase txid")
-    {
-        return Some(ConfirmationHeightAnchor {
-            anchor_block,
-            confirmation_height: 0,
-        });
-    }
-    match raw_height {
-        h if h <= 0 => {
-            debug_assert!(h == 0 || h == -1, "unexpected height ({}) from electrum", h);
-            None
-        }
-        h => {
-            let h = h as u32;
-            if h > anchor_block.height {
-                None
-            } else {
-                Some(ConfirmationHeightAnchor {
-                    anchor_block,
-                    confirmation_height: h,
-                })
-            }
-        }
-    }
-}
-
-fn populate_with_outpoints<K>(
-    client: &Client,
-    anchor_block: BlockId,
-    update: &mut ElectrumUpdate<K, ConfirmationHeightAnchor>,
-    outpoints: &mut impl Iterator<Item = OutPoint>,
-) -> Result<HashMap<Txid, Transaction>, Error> {
-    let mut full_txs = HashMap::new();
-    for outpoint in outpoints {
-        let txid = outpoint.txid;
-        let tx = client.transaction_get(&txid)?;
-        debug_assert_eq!(tx.txid(), txid);
-        let txout = match tx.output.get(outpoint.vout as usize) {
-            Some(txout) => txout,
-            None => continue,
-        };
-        // attempt to find the following transactions (alongside their chain positions), and
-        // add to our sparsechain `update`:
-        let mut has_residing = false; // tx in which the outpoint resides
-        let mut has_spending = false; // tx that spends the outpoint
-        for res in client.script_get_history(&txout.script_pubkey)? {
-            if has_residing && has_spending {
-                break;
-            }
-
-            if res.tx_hash == txid {
-                if has_residing {
-                    continue;
-                }
-                has_residing = true;
-                full_txs.insert(res.tx_hash, tx.clone());
-            } else {
-                if has_spending {
-                    continue;
-                }
-                let res_tx = match full_txs.get(&res.tx_hash) {
-                    Some(tx) => tx,
-                    None => {
-                        let res_tx = client.transaction_get(&res.tx_hash)?;
-                        full_txs.insert(res.tx_hash, res_tx);
-                        full_txs.get(&res.tx_hash).expect("just inserted")
-                    }
-                };
-                has_spending = res_tx
-                    .input
-                    .iter()
-                    .any(|txin| txin.previous_output == outpoint);
-                if !has_spending {
-                    continue;
-                }
-            };
-
-            let anchor = determine_tx_anchor(anchor_block, res.height, res.tx_hash);
-
-            let tx_entry = update.graph_update.entry(res.tx_hash).or_default();
-            if let Some(anchor) = anchor {
-                tx_entry.insert(anchor);
-            }
-        }
-    }
-    Ok(full_txs)
-}
-
-fn populate_with_txids<K>(
-    client: &Client,
-    anchor_block: BlockId,
-    update: &mut ElectrumUpdate<K, ConfirmationHeightAnchor>,
-    txids: &mut impl Iterator<Item = Txid>,
-) -> Result<(), Error> {
-    for txid in txids {
-        let tx = match client.transaction_get(&txid) {
-            Ok(tx) => tx,
-            Err(electrum_client::Error::Protocol(_)) => continue,
-            Err(other_err) => return Err(other_err),
-        };
-
-        let spk = tx
-            .output
-            .get(0)
-            .map(|txo| &txo.script_pubkey)
-            .expect("tx must have an output");
-
-        let anchor = match client
-            .script_get_history(spk)?
-            .into_iter()
-            .find(|r| r.tx_hash == txid)
-        {
-            Some(r) => determine_tx_anchor(anchor_block, r.height, txid),
-            None => continue,
-        };
-
-        let tx_entry = update.graph_update.entry(txid).or_default();
-        if let Some(anchor) = anchor {
-            tx_entry.insert(anchor);
-        }
-    }
-    Ok(())
-}
-
-fn populate_with_spks<K, I: Ord + Clone>(
-    client: &Client,
-    anchor_block: BlockId,
-    update: &mut ElectrumUpdate<K, ConfirmationHeightAnchor>,
-    spks: &mut impl Iterator<Item = (I, Script)>,
-    stop_gap: usize,
-    batch_size: usize,
-) -> Result<BTreeMap<I, (Script, bool)>, Error> {
-    let mut unused_spk_count = 0_usize;
-    let mut scanned_spks = BTreeMap::new();
-
-    loop {
-        let spks = (0..batch_size)
-            .map_while(|_| spks.next())
-            .collect::<Vec<_>>();
-        if spks.is_empty() {
-            return Ok(scanned_spks);
-        }
-
-        let spk_histories = client.batch_script_get_history(spks.iter().map(|(_, s)| s))?;
-
-        for ((spk_index, spk), spk_history) in spks.into_iter().zip(spk_histories) {
-            if spk_history.is_empty() {
-                scanned_spks.insert(spk_index, (spk, false));
-                unused_spk_count += 1;
-                if unused_spk_count > stop_gap {
-                    return Ok(scanned_spks);
-                }
-                continue;
-            } else {
-                scanned_spks.insert(spk_index, (spk, true));
-                unused_spk_count = 0;
-            }
-
-            for tx in spk_history {
-                let tx_entry = update.graph_update.entry(tx.tx_hash).or_default();
-                if let Some(anchor) = determine_tx_anchor(anchor_block, tx.height, tx.tx_hash) {
-                    tx_entry.insert(anchor);
-                }
-            }
-        }
-    }
-}
--- a/crates/electrum/src/lib.rs
+++ b/crates/electrum/src/lib.rs
@@ -20,12 +20,305 @@
 //! [`batch_transaction_get`]: ElectrumApi::batch_transaction_get
 //! [`bdk_electrum_example`]: https://github.com/LLFourn/bdk_core_staging/tree/master/bdk_electrum_example

-use bdk_chain::bitcoin::BlockHash;
-use electrum_client::{Client, ElectrumApi, Error};
-mod electrum_ext;
+use std::{
+    collections::{BTreeMap, HashMap},
+    fmt::Debug,
+};
+
 pub use bdk_chain;
+use bdk_chain::{
+    bitcoin::{hashes::hex::FromHex, BlockHash, OutPoint, Script, Transaction, Txid},
+    chain_graph::{self, ChainGraph},
+    keychain::KeychainScan,
+    sparse_chain::{self, ChainPosition, SparseChain},
+    tx_graph::TxGraph,
+    BlockId, ConfirmationTime, TxHeight,
+};
 pub use electrum_client;
-pub use electrum_ext::*;
+use electrum_client::{Client, ElectrumApi, Error};
+
+/// Trait to extend [`electrum_client::Client`] functionality.
+///
+/// Refer to [crate-level documentation] for more.
+///
+/// [crate-level documentation]: crate
+pub trait ElectrumExt {
+    /// Fetch the latest block height.
+    fn get_tip(&self) -> Result<(u32, BlockHash), Error>;
+
+    /// Scan the blockchain (via electrum) for the data specified. This returns a [`ElectrumUpdate`]
+    /// which can be transformed into a [`KeychainScan`] after we find all the missing full
+    /// transactions.
+    ///
+    /// - `local_chain`: the most recent block hashes present locally
+    /// - `keychain_spks`: keychains that we want to scan transactions for
+    /// - `txids`: transactions for which we want the updated [`ChainPosition`]s
+    /// - `outpoints`: transactions associated with these outpoints (residing, spending) that we
+    ///     want to included in the update
+    fn scan<K: Ord + Clone>(
+        &self,
+        local_chain: &BTreeMap<u32, BlockHash>,
+        keychain_spks: BTreeMap<K, impl IntoIterator<Item = (u32, Script)>>,
+        txids: impl IntoIterator<Item = Txid>,
+        outpoints: impl IntoIterator<Item = OutPoint>,
+        stop_gap: usize,
+        batch_size: usize,
+    ) -> Result<ElectrumUpdate<K, TxHeight>, Error>;
+
+    /// Convenience method to call [`scan`] without requiring a keychain.
+    ///
+    /// [`scan`]: ElectrumExt::scan
+    fn scan_without_keychain(
+        &self,
+        local_chain: &BTreeMap<u32, BlockHash>,
+        misc_spks: impl IntoIterator<Item = Script>,
+        txids: impl IntoIterator<Item = Txid>,
+        outpoints: impl IntoIterator<Item = OutPoint>,
+        batch_size: usize,
+    ) -> Result<SparseChain, Error> {
+        let spk_iter = misc_spks
+            .into_iter()
+            .enumerate()
+            .map(|(i, spk)| (i as u32, spk));
+
+        self.scan(
+            local_chain,
+            [((), spk_iter)].into(),
+            txids,
+            outpoints,
+            usize::MAX,
+            batch_size,
+        )
+        .map(|u| u.chain_update)
+    }
+}
+
+impl ElectrumExt for Client {
+    fn get_tip(&self) -> Result<(u32, BlockHash), Error> {
+        // TODO: unsubscribe when added to the client, or is there a better call to use here?
+        self.block_headers_subscribe()
+            .map(|data| (data.height as u32, data.header.block_hash()))
+    }
+
+    fn scan<K: Ord + Clone>(
+        &self,
+        local_chain: &BTreeMap<u32, BlockHash>,
+        keychain_spks: BTreeMap<K, impl IntoIterator<Item = (u32, Script)>>,
+        txids: impl IntoIterator<Item = Txid>,
+        outpoints: impl IntoIterator<Item = OutPoint>,
+        stop_gap: usize,
+        batch_size: usize,
+    ) -> Result<ElectrumUpdate<K, TxHeight>, Error> {
+        let mut request_spks = keychain_spks
+            .into_iter()
+            .map(|(k, s)| {
+                let iter = s.into_iter();
+                (k, iter)
+            })
+            .collect::<BTreeMap<K, _>>();
+        let mut scanned_spks = BTreeMap::<(K, u32), (Script, bool)>::new();
+
+        let txids = txids.into_iter().collect::<Vec<_>>();
+        let outpoints = outpoints.into_iter().collect::<Vec<_>>();
+
+        let update = loop {
+            let mut update = prepare_update(self, local_chain)?;
+
+            if !request_spks.is_empty() {
+                if !scanned_spks.is_empty() {
+                    let mut scanned_spk_iter = scanned_spks
+                        .iter()
+                        .map(|(i, (spk, _))| (i.clone(), spk.clone()));
+                    match populate_with_spks::<K, _, _>(
+                        self,
+                        &mut update,
+                        &mut scanned_spk_iter,
+                        stop_gap,
+                        batch_size,
+                    ) {
+                        Err(InternalError::Reorg) => continue,
+                        Err(InternalError::ElectrumError(e)) => return Err(e),
+                        Ok(mut spks) => scanned_spks.append(&mut spks),
+                    };
+                }
+                for (keychain, keychain_spks) in &mut request_spks {
+                    match populate_with_spks::<K, u32, _>(
+                        self,
+                        &mut update,
+                        keychain_spks,
+                        stop_gap,
+                        batch_size,
+                    ) {
+                        Err(InternalError::Reorg) => continue,
+                        Err(InternalError::ElectrumError(e)) => return Err(e),
+                        Ok(spks) => scanned_spks.extend(
+                            spks.into_iter()
+                                .map(|(spk_i, spk)| ((keychain.clone(), spk_i), spk)),
+                        ),
+                    };
+                }
+            }
+
+            match populate_with_txids(self, &mut update, &mut txids.iter().cloned()) {
+                Err(InternalError::Reorg) => continue,
+                Err(InternalError::ElectrumError(e)) => return Err(e),
+                Ok(_) => {}
+            }
+
+            match populate_with_outpoints(self, &mut update, &mut outpoints.iter().cloned()) {
+                Err(InternalError::Reorg) => continue,
+                Err(InternalError::ElectrumError(e)) => return Err(e),
+                Ok(_txs) => { /* [TODO] cache full txs to reduce bandwidth */ }
+            }
+
+            // check for reorgs during scan process
+            let our_tip = update
+                .latest_checkpoint()
+                .expect("update must have atleast one checkpoint");
+            let server_blockhash = self.block_header(our_tip.height as usize)?.block_hash();
+            if our_tip.hash != server_blockhash {
+                continue; // reorg
+            } else {
+                break update;
+            }
+        };
+
+        let last_active_index = request_spks
+            .into_keys()
+            .filter_map(|k| {
+                scanned_spks
+                    .range((k.clone(), u32::MIN)..=(k.clone(), u32::MAX))
+                    .rev()
+                    .find(|(_, (_, active))| *active)
+                    .map(|((_, i), _)| (k, *i))
+            })
+            .collect::<BTreeMap<_, _>>();
+
+        Ok(ElectrumUpdate {
+            chain_update: update,
+            last_active_indices: last_active_index,
+        })
+    }
+}
+
+/// The result of [`ElectrumExt::scan`].
+pub struct ElectrumUpdate<K, P> {
+    /// The internal [`SparseChain`] update.
+    pub chain_update: SparseChain<P>,
+    /// The last keychain script pubkey indices, which had transaction histories.
+    pub last_active_indices: BTreeMap<K, u32>,
+}
+
+impl<K, P> Default for ElectrumUpdate<K, P> {
+    fn default() -> Self {
+        Self {
+            chain_update: Default::default(),
+            last_active_indices: Default::default(),
+        }
+    }
+}
+
+impl<K, P> AsRef<SparseChain<P>> for ElectrumUpdate<K, P> {
+    fn as_ref(&self) -> &SparseChain<P> {
+        &self.chain_update
+    }
+}
+
+impl<K: Ord + Clone + Debug, P: ChainPosition> ElectrumUpdate<K, P> {
+    /// Return a list of missing full transactions that are required to [`inflate_update`].
+    ///
+    /// [`inflate_update`]: bdk_chain::chain_graph::ChainGraph::inflate_update
+    pub fn missing_full_txs<G>(&self, graph: G) -> Vec<&Txid>
+    where
+        G: AsRef<TxGraph>,
+    {
+        self.chain_update
+            .txids()
+            .filter(|(_, txid)| graph.as_ref().get_tx(*txid).is_none())
+            .map(|(_, txid)| txid)
+            .collect()
+    }
+
+    /// Transform the [`ElectrumUpdate`] into a [`KeychainScan`], which can be applied to a
+    /// `tracker`.
+    ///
+    /// This will fail if there are missing full transactions not provided via `new_txs`.
+    pub fn into_keychain_scan<CG>(
+        self,
+        new_txs: Vec<Transaction>,
+        chain_graph: &CG,
+    ) -> Result<KeychainScan<K, P>, chain_graph::NewError<P>>
+    where
+        CG: AsRef<ChainGraph<P>>,
+    {
+        Ok(KeychainScan {
+            update: chain_graph
+                .as_ref()
+                .inflate_update(self.chain_update, new_txs)?,
+            last_active_indices: self.last_active_indices,
+        })
+    }
+}
+
+impl<K: Ord + Clone + Debug> ElectrumUpdate<K, TxHeight> {
+    /// Creates [`ElectrumUpdate<K, ConfirmationTime>`] from [`ElectrumUpdate<K, TxHeight>`].
+    pub fn into_confirmation_time_update(
+        self,
+        client: &electrum_client::Client,
+    ) -> Result<ElectrumUpdate<K, ConfirmationTime>, Error> {
+        let heights = self
+            .chain_update
+            .range_txids_by_height(..TxHeight::Unconfirmed)
+            .map(|(h, _)| match h {
+                TxHeight::Confirmed(h) => *h,
+                _ => unreachable!("already filtered out unconfirmed"),
+            })
+            .collect::<Vec<u32>>();
+
+        let height_to_time = heights
+            .clone()
+            .into_iter()
+            .zip(
+                client
+                    .batch_block_header(heights)?
+                    .into_iter()
+                    .map(|bh| bh.time as u64),
+            )
+            .collect::<HashMap<u32, u64>>();
+
+        let mut new_update = SparseChain::<ConfirmationTime>::from_checkpoints(
+            self.chain_update.range_checkpoints(..),
+        );
+
+        for &(tx_height, txid) in self.chain_update.txids() {
+            let conf_time = match tx_height {
+                TxHeight::Confirmed(height) => ConfirmationTime::Confirmed {
+                    height,
+                    time: height_to_time[&height],
+                },
+                TxHeight::Unconfirmed => ConfirmationTime::Unconfirmed,
+            };
+            let _ = new_update.insert_tx(txid, conf_time).expect("must insert");
+        }
+
+        Ok(ElectrumUpdate {
+            chain_update: new_update,
+            last_active_indices: self.last_active_indices,
+        })
+    }
+}
+
+#[derive(Debug)]
+enum InternalError {
+    ElectrumError(Error),
+    Reorg,
+}
+
+impl From<electrum_client::Error> for InternalError {
+    fn from(value: electrum_client::Error) -> Self {
+        Self::ElectrumError(value)
+    }
+}

 fn get_tip(client: &Client) -> Result<(u32, BlockHash), Error> {
    // TODO: unsubscribe when added to the client, or is there a better call to use here?
@@ -33,3 +326,263 @@ fn get_tip(client: &Client) -> Result<(u32, BlockHash), Error> {
        .block_headers_subscribe()
        .map(|data| (data.height as u32, data.header.block_hash()))
 }
+
+/// Prepare an update sparsechain "template" based on the checkpoints of the `local_chain`.
+fn prepare_update(
+    client: &Client,
+    local_chain: &BTreeMap<u32, BlockHash>,
+) -> Result<SparseChain, Error> {
+    let mut update = SparseChain::default();
+
+    // Find the local chain block that is still there so our update can connect to the local chain.
+    for (&existing_height, &existing_hash) in local_chain.iter().rev() {
+        // TODO: a batch request may be safer, as a reorg that happens when we are obtaining
+        //       `block_header`s will result in inconsistencies
+        let current_hash = client.block_header(existing_height as usize)?.block_hash();
+        let _ = update
+            .insert_checkpoint(BlockId {
+                height: existing_height,
+                hash: current_hash,
+            })
+            .expect("This never errors because we are working with a fresh chain");
+
+        if current_hash == existing_hash {
+            break;
+        }
+    }
+
+    // Insert the new tip so new transactions will be accepted into the sparsechain.
+    let tip = {
+        let (height, hash) = get_tip(client)?;
+        BlockId { height, hash }
+    };
+    if let Err(failure) = update.insert_checkpoint(tip) {
+        match failure {
+            sparse_chain::InsertCheckpointError::HashNotMatching { .. } => {
+                // There has been a re-org before we even begin scanning addresses.
+                // Just recursively call (this should never happen).
+                return prepare_update(client, local_chain);
+            }
+        }
+    }
+
+    Ok(update)
+}
+
+/// This atrocity is required because electrum thinks a height of 0 means "unconfirmed", but there is
+/// such thing as a genesis block.
+///
+/// We contain an expectation for the genesis coinbase txid to always have a chain position of
+/// [`TxHeight::Confirmed(0)`].
+fn determine_tx_height(raw_height: i32, tip_height: u32, txid: Txid) -> TxHeight {
+    if txid
+        == Txid::from_hex("4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b")
+            .expect("must deserialize genesis coinbase txid")
+    {
+        return TxHeight::Confirmed(0);
+    }
+    match raw_height {
+        h if h <= 0 => {
+            debug_assert!(
+                h == 0 || h == -1,
+                "unexpected height ({}) from electrum server",
+                h
+            );
+            TxHeight::Unconfirmed
+        }
+        h => {
+            let h = h as u32;
+            if h > tip_height {
+                TxHeight::Unconfirmed
+            } else {
+                TxHeight::Confirmed(h)
+            }
+        }
+    }
+}
+
+/// Populates the update [`SparseChain`] with related transactions and associated [`ChainPosition`]s
+/// of the provided `outpoints` (this is the tx which contains the outpoint and the one spending the
+/// outpoint).
+///
+/// Unfortunately, this is awkward to implement as electrum does not provide such an API. Instead, we
+/// will get the tx history of the outpoint's spk and try to find the containing tx and the
+/// spending tx.
+fn populate_with_outpoints(
+    client: &Client,
+    update: &mut SparseChain,
+    outpoints: &mut impl Iterator<Item = OutPoint>,
+) -> Result<HashMap<Txid, Transaction>, InternalError> {
+    let tip = update
+        .latest_checkpoint()
+        .expect("update must atleast have one checkpoint");
+
+    let mut full_txs = HashMap::new();
+    for outpoint in outpoints {
+        let txid = outpoint.txid;
+        let tx = client.transaction_get(&txid)?;
+        debug_assert_eq!(tx.txid(), txid);
+        let txout = match tx.output.get(outpoint.vout as usize) {
+            Some(txout) => txout,
+            None => continue,
+        };
+
+        // attempt to find the following transactions (alongside their chain positions), and
+        // add to our sparsechain `update`:
+        let mut has_residing = false; // tx in which the outpoint resides
+        let mut has_spending = false; // tx that spends the outpoint
+        for res in client.script_get_history(&txout.script_pubkey)? {
+            if has_residing && has_spending {
+                break;
+            }
+
+            if res.tx_hash == txid {
+                if has_residing {
+                    continue;
+                }
+                has_residing = true;
+                full_txs.insert(res.tx_hash, tx.clone());
+            } else {
+                if has_spending {
+                    continue;
+                }
+                let res_tx = match full_txs.get(&res.tx_hash) {
+                    Some(tx) => tx,
+                    None => {
+                        let res_tx = client.transaction_get(&res.tx_hash)?;
+                        full_txs.insert(res.tx_hash, res_tx);
+                        full_txs.get(&res.tx_hash).expect("just inserted")
+                    }
+                };
+                has_spending = res_tx
+                    .input
+                    .iter()
+                    .any(|txin| txin.previous_output == outpoint);
+                if !has_spending {
+                    continue;
+                }
+            };
+
+            let tx_height = determine_tx_height(res.height, tip.height, res.tx_hash);
+
+            if let Err(failure) = update.insert_tx(res.tx_hash, tx_height) {
+                match failure {
+                    sparse_chain::InsertTxError::TxTooHigh { .. } => {
+                        unreachable!("we should never encounter this as we ensured height <= tip");
+                    }
+                    sparse_chain::InsertTxError::TxMovedUnexpectedly { .. } => {
+                        return Err(InternalError::Reorg);
+                    }
+                }
+            }
+        }
+    }
+    Ok(full_txs)
+}
+
+/// Populate an update [`SparseChain`] with transactions (and associated block positions) from
+/// the given `txids`.
+fn populate_with_txids(
+    client: &Client,
+    update: &mut SparseChain,
+    txids: &mut impl Iterator<Item = Txid>,
+) -> Result<(), InternalError> {
+    let tip = update
+        .latest_checkpoint()
+        .expect("update must have atleast one checkpoint");
+    for txid in txids {
+        let tx = match client.transaction_get(&txid) {
+            Ok(tx) => tx,
+            Err(electrum_client::Error::Protocol(_)) => continue,
+            Err(other_err) => return Err(other_err.into()),
+        };
+
+        let spk = tx
+            .output
+            .get(0)
+            .map(|txo| &txo.script_pubkey)
+            .expect("tx must have an output");
+
+        let tx_height = match client
+            .script_get_history(spk)?
+            .into_iter()
+            .find(|r| r.tx_hash == txid)
+        {
+            Some(r) => determine_tx_height(r.height, tip.height, r.tx_hash),
+            None => continue,
+        };
+
+        if let Err(failure) = update.insert_tx(txid, tx_height) {
+            match failure {
+                sparse_chain::InsertTxError::TxTooHigh { .. } => {
+                    unreachable!("we should never encounter this as we ensured height <= tip");
+                }
+                sparse_chain::InsertTxError::TxMovedUnexpectedly { .. } => {
+                    return Err(InternalError::Reorg);
+                }
+            }
+        }
+    }
+    Ok(())
+}
+
+/// Populate an update [`SparseChain`] with transactions (and associated block positions) from
+/// the transaction history of the provided `spk`s.
+fn populate_with_spks<K, I, S>(
+    client: &Client,
+    update: &mut SparseChain,
+    spks: &mut S,
+    stop_gap: usize,
+    batch_size: usize,
+) -> Result<BTreeMap<I, (Script, bool)>, InternalError>
+where
+    K: Ord + Clone,
+    I: Ord + Clone,
+    S: Iterator<Item = (I, Script)>,
+{
+    let tip = update.latest_checkpoint().map_or(0, |cp| cp.height);
+    let mut unused_spk_count = 0_usize;
+    let mut scanned_spks = BTreeMap::new();
+
+    loop {
+        let spks = (0..batch_size)
+            .map_while(|_| spks.next())
+            .collect::<Vec<_>>();
+        if spks.is_empty() {
+            return Ok(scanned_spks);
+        }
+
+        let spk_histories = client.batch_script_get_history(spks.iter().map(|(_, s)| s))?;
+
+        for ((spk_index, spk), spk_history) in spks.into_iter().zip(spk_histories) {
+            if spk_history.is_empty() {
+                scanned_spks.insert(spk_index, (spk, false));
+                unused_spk_count += 1;
+                if unused_spk_count > stop_gap {
+                    return Ok(scanned_spks);
+                }
+                continue;
+            } else {
+                scanned_spks.insert(spk_index, (spk, true));
+                unused_spk_count = 0;
+            }
+
+            for tx in spk_history {
+                let tx_height = determine_tx_height(tx.height, tip, tx.tx_hash);
+
+                if let Err(failure) = update.insert_tx(tx.tx_hash, tx_height) {
+                    match failure {
+                        sparse_chain::InsertTxError::TxTooHigh { .. } => {
+                            unreachable!(
+                                "we should never encounter this as we ensured height <= tip"
+                            );
+                        }
+                        sparse_chain::InsertTxError::TxMovedUnexpectedly { .. } => {
+                            return Err(InternalError::Reorg);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
--- a/crates/esplora/Cargo.toml
+++ b/crates/esplora/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "bdk_esplora"
-version = "0.3.0"
+version = "0.2.0"
 edition = "2021"
 homepage = "https://bitcoindevkit.org"
 repository = "https://github.com/bitcoindevkit/bdk"
@@ -12,18 +12,13 @@ readme = "README.md"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

 [dependencies]
-bdk_chain = { path = "../chain", version = "0.5.0", default-features = false, features = ["serde", "miniscript"] }
-esplora-client = { version = "0.5", default-features = false }
+bdk_chain = { path = "../chain", version = "0.4.0", features = ["serde", "miniscript"] }
+esplora-client = { version = "0.3", default-features = false }
 async-trait = { version = "0.1.66", optional = true }
 futures = { version = "0.3.26", optional = true }

-# use these dependencies if you need to enable their /no-std features
-bitcoin = { version = "0.29", optional = true, default-features = false }
-miniscript = { version = "9.0.0", optional = true, default-features = false }
-
 [features]
-default = ["std", "async-https", "blocking"]
-std = ["bdk_chain/std"]
+default = ["async-https", "blocking"]
 async = ["async-trait", "futures", "esplora-client/async"]
 async-https = ["async", "esplora-client/async-https"]
 blocking = ["esplora-client/blocking"]
--- a/crates/esplora/README.md
+++ b/crates/esplora/README.md
@@ -9,17 +9,17 @@ There are two versions of the extension trait (blocking and async).

 For blocking-only:
 ```toml
-bdk_esplora = { version = "0.3", features = ["blocking"] }
+bdk_esplora = { version = "0.1", features = ["blocking"] }
 ```

 For async-only:
 ```toml
-bdk_esplora = { version = "0.3", features = ["async"] }
+bdk_esplora = { version = "0.1", features = ["async"] }
 ```

 For async-only (with https):
 ```toml
-bdk_esplora = { version = "0.3", features = ["async-https"] }
+bdk_esplora = { version = "0.1", features = ["async-https"] }
 ```

 To use the extension traits:
@@ -27,7 +27,7 @@ To use the extension traits:
 // for blocking
 use bdk_esplora::EsploraExt;
 // for async
-// use bdk_esplora::EsploraAsyncExt;
+use bdk_esplora::EsploraAsyncExt;
 ```

 For full examples, refer to [`example-crates/wallet_esplora`](https://github.com/bitcoindevkit/bdk/tree/master/example-crates/wallet_esplora) (blocking) and [`example-crates/wallet_esplora_async`](https://github.com/bitcoindevkit/bdk/tree/master/example-crates/wallet_esplora_async).
--- a/crates/esplora/src/async_ext.rs
+++ b/crates/esplora/src/async_ext.rs
@@ -1,14 +1,16 @@
+use std::collections::BTreeMap;
+
 use async_trait::async_trait;
 use bdk_chain::{
    bitcoin::{BlockHash, OutPoint, Script, Txid},
-    collections::BTreeMap,
-    keychain::LocalUpdate,
-    BlockId, ConfirmationTimeAnchor,
+    chain_graph::ChainGraph,
+    keychain::KeychainScan,
+    sparse_chain, BlockId, ConfirmationTime,
 };
-use esplora_client::{Error, OutputStatus, TxStatus};
-use futures::{stream::FuturesOrdered, TryStreamExt};
+use esplora_client::{Error, OutputStatus};
+use futures::stream::{FuturesOrdered, TryStreamExt};

-use crate::map_confirmation_time_anchor;
+use crate::map_confirmation_time;

 /// Trait to extend [`esplora_client::AsyncClient`] functionality.
 ///
@@ -17,21 +19,23 @@ use crate::map_confirmation_time_anchor;
 ///
 /// [`EsploraExt`]: crate::EsploraExt
 /// [crate-level documentation]: crate
+#[cfg(feature = "async")]
 #[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
 #[cfg_attr(not(target_arch = "wasm32"), async_trait)]
 pub trait EsploraAsyncExt {
-    /// Scan the blockchain (via esplora) for the data specified and returns a
-    /// [`LocalUpdate<K, ConfirmationTimeAnchor>`].
+    /// Scan the blockchain (via esplora) for the data specified and returns a [`KeychainScan`].
    ///
    /// - `local_chain`: the most recent block hashes present locally
    /// - `keychain_spks`: keychains that we want to scan transactions for
-    /// - `txids`: transactions for which we want updated [`ConfirmationTimeAnchor`]s
+    /// - `txids`: transactions for which we want updated [`ChainPosition`]s
    /// - `outpoints`: transactions associated with these outpoints (residing, spending) that we
    ///     want to included in the update
    ///
    /// The scan for each keychain stops after a gap of `stop_gap` script pubkeys with no associated
    /// transactions. `parallel_requests` specifies the max number of HTTP requests to make in
    /// parallel.
+    ///
+    /// [`ChainPosition`]: bdk_chain::sparse_chain::ChainPosition
    #[allow(clippy::result_large_err)] // FIXME
    async fn scan<K: Ord + Clone + Send>(
        &self,
@@ -44,7 +48,7 @@ pub trait EsploraAsyncExt {
        outpoints: impl IntoIterator<IntoIter = impl Iterator<Item = OutPoint> + Send> + Send,
        stop_gap: usize,
        parallel_requests: usize,
-    ) -> Result<LocalUpdate<K, ConfirmationTimeAnchor>, Error>;
+    ) -> Result<KeychainScan<K, ConfirmationTime>, Error>;

    /// Convenience method to call [`scan`] without requiring a keychain.
    ///
@@ -57,26 +61,30 @@ pub trait EsploraAsyncExt {
        txids: impl IntoIterator<IntoIter = impl Iterator<Item = Txid> + Send> + Send,
        outpoints: impl IntoIterator<IntoIter = impl Iterator<Item = OutPoint> + Send> + Send,
        parallel_requests: usize,
-    ) -> Result<LocalUpdate<(), ConfirmationTimeAnchor>, Error> {
-        self.scan(
-            local_chain,
-            [(
-                (),
-                misc_spks
-                    .into_iter()
-                    .enumerate()
-                    .map(|(i, spk)| (i as u32, spk)),
-            )]
-            .into(),
-            txids,
-            outpoints,
-            usize::MAX,
-            parallel_requests,
-        )
-        .await
+    ) -> Result<ChainGraph<ConfirmationTime>, Error> {
+        let wallet_scan = self
+            .scan(
+                local_chain,
+                [(
+                    (),
+                    misc_spks
+                        .into_iter()
+                        .enumerate()
+                        .map(|(i, spk)| (i as u32, spk)),
+                )]
+                .into(),
+                txids,
+                outpoints,
+                usize::MAX,
+                parallel_requests,
+            )
+            .await?;
+
+        Ok(wallet_scan.update)
    }
 }

+#[cfg(feature = "async")]
 #[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
 #[cfg_attr(not(target_arch = "wasm32"), async_trait)]
 impl EsploraAsyncExt for esplora_client::AsyncClient {
@@ -92,35 +100,47 @@ impl EsploraAsyncExt for esplora_client::AsyncClient {
        outpoints: impl IntoIterator<IntoIter = impl Iterator<Item = OutPoint> + Send> + Send,
        stop_gap: usize,
        parallel_requests: usize,
-    ) -> Result<LocalUpdate<K, ConfirmationTimeAnchor>, Error> {
-        let parallel_requests = Ord::max(parallel_requests, 1);
+    ) -> Result<KeychainScan<K, ConfirmationTime>, Error> {
+        let txids = txids.into_iter();
+        let outpoints = outpoints.into_iter();
+        let parallel_requests = parallel_requests.max(1);
+        let mut scan = KeychainScan::default();
+        let update = &mut scan.update;
+        let last_active_indices = &mut scan.last_active_indices;

-        let (mut update, tip_at_start) = loop {
-            let mut update = LocalUpdate::<K, ConfirmationTimeAnchor>::default();
-
-            for (&height, &original_hash) in local_chain.iter().rev() {
-                let update_block_id = BlockId {
-                    height,
-                    hash: self.get_block_hash(height).await?,
-                };
-                let _ = update
-                    .chain
-                    .insert_block(update_block_id)
-                    .expect("cannot repeat height here");
-                if update_block_id.hash == original_hash {
-                    break;
+        for (&height, &original_hash) in local_chain.iter().rev() {
+            let update_block_id = BlockId {
+                height,
+                hash: self.get_block_hash(height).await?,
+            };
+            let _ = update
+                .insert_checkpoint(update_block_id)
+                .expect("cannot repeat height here");
+            if update_block_id.hash == original_hash {
+                break;
+            }
+        }
+        let tip_at_start = BlockId {
+            height: self.get_height().await?,
+            hash: self.get_tip_hash().await?,
+        };
+        if let Err(failure) = update.insert_checkpoint(tip_at_start) {
+            match failure {
+                sparse_chain::InsertCheckpointError::HashNotMatching { .. } => {
+                    // there was a re-org before we started scanning. We haven't consumed any iterators, so calling this function recursively is safe.
+                    return EsploraAsyncExt::scan(
+                        self,
+                        local_chain,
+                        keychain_spks,
+                        txids,
+                        outpoints,
+                        stop_gap,
+                        parallel_requests,
+                    )
+                    .await;
                }
            }
-
-            let tip_at_start = BlockId {
-                height: self.get_height().await?,
-                hash: self.get_tip_hash().await?,
-            };
-
-            if update.chain.insert_block(tip_at_start).is_ok() {
-                break (update, tip_at_start);
-            }
-        };
+        }

        for (keychain, spks) in keychain_spks {
            let mut spks = spks.into_iter();
@@ -129,7 +149,7 @@ impl EsploraAsyncExt for esplora_client::AsyncClient {
            type IndexWithTxs = (u32, Vec<esplora_client::Tx>);

            loop {
-                let futures = (0..parallel_requests)
+                let futures: FuturesOrdered<_> = (0..parallel_requests)
                    .filter_map(|_| {
                        let (index, script) = spks.next()?;
                        let client = self.clone();
@@ -160,11 +180,13 @@ impl EsploraAsyncExt for esplora_client::AsyncClient {
                            Result::<_, esplora_client::Error>::Ok((index, related_txs))
                        })
                    })
-                    .collect::<FuturesOrdered<_>>();
+                    .collect();

                let n_futures = futures.len();

-                for (index, related_txs) in futures.try_collect::<Vec<IndexWithTxs>>().await? {
+                let idx_with_tx: Vec<IndexWithTxs> = futures.try_collect().await?;
+
+                for (index, related_txs) in idx_with_tx {
                    if related_txs.is_empty() {
                        empty_scripts += 1;
                    } else {
@@ -172,11 +194,22 @@ impl EsploraAsyncExt for esplora_client::AsyncClient {
                        empty_scripts = 0;
                    }
                    for tx in related_txs {
-                        let anchor = map_confirmation_time_anchor(&tx.status, tip_at_start);
+                        let confirmation_time =
+                            map_confirmation_time(&tx.status, tip_at_start.height);

-                        let _ = update.graph.insert_tx(tx.to_tx());
-                        if let Some(anchor) = anchor {
-                            let _ = update.graph.insert_anchor(tx.txid, anchor);
+                        if let Err(failure) = update.insert_tx(tx.to_tx(), confirmation_time) {
+                            use bdk_chain::{
+                                chain_graph::InsertTxError, sparse_chain::InsertTxError::*,
+                            };
+                            match failure {
+                                InsertTxError::Chain(TxTooHigh { .. }) => {
+                                    unreachable!("chain position already checked earlier")
+                                }
+                                InsertTxError::Chain(TxMovedUnexpectedly { .. })
+                                | InsertTxError::UnresolvableConflict(_) => {
+                                    /* implies reorg during a scan. We deal with that below */
+                                }
+                            }
                        }
                    }
                }
@@ -187,37 +220,36 @@ impl EsploraAsyncExt for esplora_client::AsyncClient {
            }

            if let Some(last_active_index) = last_active_index {
-                update.keychain.insert(keychain, last_active_index);
+                last_active_indices.insert(keychain, last_active_index);
            }
        }

-        for txid in txids.into_iter() {
-            if update.graph.get_tx(txid).is_none() {
-                match self.get_tx(&txid).await? {
-                    Some(tx) => {
-                        let _ = update.graph.insert_tx(tx);
+        for txid in txids {
+            let (tx, tx_status) =
+                match (self.get_tx(&txid).await?, self.get_tx_status(&txid).await?) {
+                    (Some(tx), Some(tx_status)) => (tx, tx_status),
+                    _ => continue,
+                };
+
+            let confirmation_time = map_confirmation_time(&tx_status, tip_at_start.height);
+
+            if let Err(failure) = update.insert_tx(tx, confirmation_time) {
+                use bdk_chain::{chain_graph::InsertTxError, sparse_chain::InsertTxError::*};
+                match failure {
+                    InsertTxError::Chain(TxTooHigh { .. }) => {
+                        unreachable!("chain position already checked earlier")
                    }
-                    None => continue,
-                }
-            }
-            match self.get_tx_status(&txid).await? {
-                tx_status if tx_status.confirmed => {
-                    if let Some(anchor) = map_confirmation_time_anchor(&tx_status, tip_at_start) {
-                        let _ = update.graph.insert_anchor(txid, anchor);
+                    InsertTxError::Chain(TxMovedUnexpectedly { .. })
+                    | InsertTxError::UnresolvableConflict(_) => {
+                        /* implies reorg during a scan. We deal with that below */
                    }
                }
-                _ => continue,
            }
        }

-        for op in outpoints.into_iter() {
+        for op in outpoints {
            let mut op_txs = Vec::with_capacity(2);
-            if let (
-                Some(tx),
-                tx_status @ TxStatus {
-                    confirmed: true, ..
-                },
-            ) = (
+            if let (Some(tx), Some(tx_status)) = (
                self.get_tx(&op.txid).await?,
                self.get_tx_status(&op.txid).await?,
            ) {
@@ -235,24 +267,40 @@ impl EsploraAsyncExt for esplora_client::AsyncClient {
            }

            for (tx, status) in op_txs {
-                let txid = tx.txid();
-                let anchor = map_confirmation_time_anchor(&status, tip_at_start);
+                let confirmation_time = map_confirmation_time(&status, tip_at_start.height);

-                let _ = update.graph.insert_tx(tx);
-                if let Some(anchor) = anchor {
-                    let _ = update.graph.insert_anchor(txid, anchor);
+                if let Err(failure) = update.insert_tx(tx, confirmation_time) {
+                    use bdk_chain::{chain_graph::InsertTxError, sparse_chain::InsertTxError::*};
+                    match failure {
+                        InsertTxError::Chain(TxTooHigh { .. }) => {
+                            unreachable!("chain position already checked earlier")
+                        }
+                        InsertTxError::Chain(TxMovedUnexpectedly { .. })
+                        | InsertTxError::UnresolvableConflict(_) => {
+                            /* implies reorg during a scan. We deal with that below */
+                        }
+                    }
                }
            }
        }

-        if tip_at_start.hash != self.get_block_hash(tip_at_start.height).await? {
-            // A reorg occurred, so let's find out where all the txids we found are now in the chain
+        let reorg_occurred = {
+            if let Some(checkpoint) = update.chain().latest_checkpoint() {
+                self.get_block_hash(checkpoint.height).await? != checkpoint.hash
+            } else {
+                false
+            }
+        };
+
+        if reorg_occurred {
+            // A reorg occurred, so let's find out where all the txids we found are in the chain now.
+            // XXX: collect required because of weird type naming issues
            let txids_found = update
-                .graph
-                .full_txs()
-                .map(|tx_node| tx_node.txid)
+                .chain()
+                .txids()
+                .map(|(_, txid)| *txid)
                .collect::<Vec<_>>();
-            update.chain = EsploraAsyncExt::scan_without_keychain(
+            scan.update = EsploraAsyncExt::scan_without_keychain(
                self,
                local_chain,
                [],
@@ -260,10 +308,9 @@ impl EsploraAsyncExt for esplora_client::AsyncClient {
                [],
                parallel_requests,
            )
-            .await?
-            .chain;
+            .await?;
        }

-        Ok(update)
+        Ok(scan)
    }
 }
--- a/crates/esplora/src/blocking_ext.rs
+++ b/crates/esplora/src/blocking_ext.rs
@@ -1,10 +1,14 @@
-use bdk_chain::bitcoin::{BlockHash, OutPoint, Script, Txid};
-use bdk_chain::collections::BTreeMap;
-use bdk_chain::BlockId;
-use bdk_chain::{keychain::LocalUpdate, ConfirmationTimeAnchor};
-use esplora_client::{Error, OutputStatus, TxStatus};
+use std::collections::BTreeMap;

-use crate::map_confirmation_time_anchor;
+use bdk_chain::{
+    bitcoin::{BlockHash, OutPoint, Script, Txid},
+    chain_graph::ChainGraph,
+    keychain::KeychainScan,
+    sparse_chain, BlockId, ConfirmationTime,
+};
+use esplora_client::{Error, OutputStatus};
+
+use crate::map_confirmation_time;

 /// Trait to extend [`esplora_client::BlockingClient`] functionality.
 ///
@@ -12,18 +16,19 @@ use crate::map_confirmation_time_anchor;
 ///
 /// [crate-level documentation]: crate
 pub trait EsploraExt {
-    /// Scan the blockchain (via esplora) for the data specified and returns a
-    /// [`LocalUpdate<K, ConfirmationTimeAnchor>`].
+    /// Scan the blockchain (via esplora) for the data specified and returns a [`KeychainScan`].
    ///
    /// - `local_chain`: the most recent block hashes present locally
    /// - `keychain_spks`: keychains that we want to scan transactions for
-    /// - `txids`: transactions for which we want updated [`ConfirmationTimeAnchor`]s
+    /// - `txids`: transactions for which we want updated [`ChainPosition`]s
    /// - `outpoints`: transactions associated with these outpoints (residing, spending) that we
    ///     want to included in the update
    ///
    /// The scan for each keychain stops after a gap of `stop_gap` script pubkeys with no associated
    /// transactions. `parallel_requests` specifies the max number of HTTP requests to make in
    /// parallel.
+    ///
+    /// [`ChainPosition`]: bdk_chain::sparse_chain::ChainPosition
    #[allow(clippy::result_large_err)] // FIXME
    fn scan<K: Ord + Clone>(
        &self,
@@ -33,7 +38,7 @@ pub trait EsploraExt {
        outpoints: impl IntoIterator<Item = OutPoint>,
        stop_gap: usize,
        parallel_requests: usize,
-    ) -> Result<LocalUpdate<K, ConfirmationTimeAnchor>, Error>;
+    ) -> Result<KeychainScan<K, ConfirmationTime>, Error>;

    /// Convenience method to call [`scan`] without requiring a keychain.
    ///
@@ -46,8 +51,8 @@ pub trait EsploraExt {
        txids: impl IntoIterator<Item = Txid>,
        outpoints: impl IntoIterator<Item = OutPoint>,
        parallel_requests: usize,
-    ) -> Result<LocalUpdate<(), ConfirmationTimeAnchor>, Error> {
-        self.scan(
+    ) -> Result<ChainGraph<ConfirmationTime>, Error> {
+        let wallet_scan = self.scan(
            local_chain,
            [(
                (),
@@ -61,7 +66,9 @@ pub trait EsploraExt {
            outpoints,
            usize::MAX,
            parallel_requests,
-        )
+        )?;
+
+        Ok(wallet_scan.update)
    }
 }

@@ -74,35 +81,44 @@ impl EsploraExt for esplora_client::BlockingClient {
        outpoints: impl IntoIterator<Item = OutPoint>,
        stop_gap: usize,
        parallel_requests: usize,
-    ) -> Result<LocalUpdate<K, ConfirmationTimeAnchor>, Error> {
-        let parallel_requests = Ord::max(parallel_requests, 1);
+    ) -> Result<KeychainScan<K, ConfirmationTime>, Error> {
+        let parallel_requests = parallel_requests.max(1);
+        let mut scan = KeychainScan::default();
+        let update = &mut scan.update;
+        let last_active_indices = &mut scan.last_active_indices;

-        let (mut update, tip_at_start) = loop {
-            let mut update = LocalUpdate::<K, ConfirmationTimeAnchor>::default();
-
-            for (&height, &original_hash) in local_chain.iter().rev() {
-                let update_block_id = BlockId {
-                    height,
-                    hash: self.get_block_hash(height)?,
-                };
-                let _ = update
-                    .chain
-                    .insert_block(update_block_id)
-                    .expect("cannot repeat height here");
-                if update_block_id.hash == original_hash {
-                    break;
+        for (&height, &original_hash) in local_chain.iter().rev() {
+            let update_block_id = BlockId {
+                height,
+                hash: self.get_block_hash(height)?,
+            };
+            let _ = update
+                .insert_checkpoint(update_block_id)
+                .expect("cannot repeat height here");
+            if update_block_id.hash == original_hash {
+                break;
+            }
+        }
+        let tip_at_start = BlockId {
+            height: self.get_height()?,
+            hash: self.get_tip_hash()?,
+        };
+        if let Err(failure) = update.insert_checkpoint(tip_at_start) {
+            match failure {
+                sparse_chain::InsertCheckpointError::HashNotMatching { .. } => {
+                    // there was a re-org before we started scanning. We haven't consumed any iterators, so calling this function recursively is safe.
+                    return EsploraExt::scan(
+                        self,
+                        local_chain,
+                        keychain_spks,
+                        txids,
+                        outpoints,
+                        stop_gap,
+                        parallel_requests,
+                    );
                }
            }
-
-            let tip_at_start = BlockId {
-                height: self.get_height()?,
-                hash: self.get_tip_hash()?,
-            };
-
-            if update.chain.insert_block(tip_at_start).is_ok() {
-                break (update, tip_at_start);
-            }
-        };
+        }

        for (keychain, spks) in keychain_spks {
            let mut spks = spks.into_iter();
@@ -155,11 +171,22 @@ impl EsploraExt for esplora_client::BlockingClient {
                        empty_scripts = 0;
                    }
                    for tx in related_txs {
-                        let anchor = map_confirmation_time_anchor(&tx.status, tip_at_start);
+                        let confirmation_time =
+                            map_confirmation_time(&tx.status, tip_at_start.height);

-                        let _ = update.graph.insert_tx(tx.to_tx());
-                        if let Some(anchor) = anchor {
-                            let _ = update.graph.insert_anchor(tx.txid, anchor);
+                        if let Err(failure) = update.insert_tx(tx.to_tx(), confirmation_time) {
+                            use bdk_chain::{
+                                chain_graph::InsertTxError, sparse_chain::InsertTxError::*,
+                            };
+                            match failure {
+                                InsertTxError::Chain(TxTooHigh { .. }) => {
+                                    unreachable!("chain position already checked earlier")
+                                }
+                                InsertTxError::Chain(TxMovedUnexpectedly { .. })
+                                | InsertTxError::UnresolvableConflict(_) => {
+                                    /* implies reorg during a scan. We deal with that below */
+                                }
+                            }
                        }
                    }
                }
@@ -170,39 +197,36 @@ impl EsploraExt for esplora_client::BlockingClient {
            }

            if let Some(last_active_index) = last_active_index {
-                update.keychain.insert(keychain, last_active_index);
+                last_active_indices.insert(keychain, last_active_index);
            }
        }

        for txid in txids.into_iter() {
-            if update.graph.get_tx(txid).is_none() {
-                match self.get_tx(&txid)? {
-                    Some(tx) => {
-                        let _ = update.graph.insert_tx(tx);
-                    }
-                    None => continue,
-                }
-            }
-            match self.get_tx_status(&txid)? {
-                tx_status @ TxStatus {
-                    confirmed: true, ..
-                } => {
-                    if let Some(anchor) = map_confirmation_time_anchor(&tx_status, tip_at_start) {
-                        let _ = update.graph.insert_anchor(txid, anchor);
-                    }
-                }
+            let (tx, tx_status) = match (self.get_tx(&txid)?, self.get_tx_status(&txid)?) {
+                (Some(tx), Some(tx_status)) => (tx, tx_status),
                _ => continue,
+            };
+
+            let confirmation_time = map_confirmation_time(&tx_status, tip_at_start.height);
+
+            if let Err(failure) = update.insert_tx(tx, confirmation_time) {
+                use bdk_chain::{chain_graph::InsertTxError, sparse_chain::InsertTxError::*};
+                match failure {
+                    InsertTxError::Chain(TxTooHigh { .. }) => {
+                        unreachable!("chain position already checked earlier")
+                    }
+                    InsertTxError::Chain(TxMovedUnexpectedly { .. })
+                    | InsertTxError::UnresolvableConflict(_) => {
+                        /* implies reorg during a scan. We deal with that below */
+                    }
+                }
            }
        }

        for op in outpoints.into_iter() {
            let mut op_txs = Vec::with_capacity(2);
-            if let (
-                Some(tx),
-                tx_status @ TxStatus {
-                    confirmed: true, ..
-                },
-            ) = (self.get_tx(&op.txid)?, self.get_tx_status(&op.txid)?)
+            if let (Some(tx), Some(tx_status)) =
+                (self.get_tx(&op.txid)?, self.get_tx_status(&op.txid)?)
            {
                op_txs.push((tx, tx_status));
                if let Some(OutputStatus {
@@ -218,34 +242,49 @@ impl EsploraExt for esplora_client::BlockingClient {
            }

            for (tx, status) in op_txs {
-                let txid = tx.txid();
-                let anchor = map_confirmation_time_anchor(&status, tip_at_start);
+                let confirmation_time = map_confirmation_time(&status, tip_at_start.height);

-                let _ = update.graph.insert_tx(tx);
-                if let Some(anchor) = anchor {
-                    let _ = update.graph.insert_anchor(txid, anchor);
+                if let Err(failure) = update.insert_tx(tx, confirmation_time) {
+                    use bdk_chain::{chain_graph::InsertTxError, sparse_chain::InsertTxError::*};
+                    match failure {
+                        InsertTxError::Chain(TxTooHigh { .. }) => {
+                            unreachable!("chain position already checked earlier")
+                        }
+                        InsertTxError::Chain(TxMovedUnexpectedly { .. })
+                        | InsertTxError::UnresolvableConflict(_) => {
+                            /* implies reorg during a scan. We deal with that below */
+                        }
+                    }
                }
            }
        }

-        if tip_at_start.hash != self.get_block_hash(tip_at_start.height)? {
-            // A reorg occurred, so let's find out where all the txids we found are now in the chain
+        let reorg_occurred = {
+            if let Some(checkpoint) = update.chain().latest_checkpoint() {
+                self.get_block_hash(checkpoint.height)? != checkpoint.hash
+            } else {
+                false
+            }
+        };
+
+        if reorg_occurred {
+            // A reorg occurred, so let's find out where all the txids we found are now in the chain.
+            // XXX: collect required because of weird type naming issues
            let txids_found = update
-                .graph
-                .full_txs()
-                .map(|tx_node| tx_node.txid)
+                .chain()
+                .txids()
+                .map(|(_, txid)| *txid)
                .collect::<Vec<_>>();
-            update.chain = EsploraExt::scan_without_keychain(
+            scan.update = EsploraExt::scan_without_keychain(
                self,
                local_chain,
                [],
                txids_found,
                [],
                parallel_requests,
-            )?
-            .chain;
+            )?;
        }

-        Ok(update)
+        Ok(scan)
    }
 }
--- a/crates/esplora/src/lib.rs
+++ b/crates/esplora/src/lib.rs
@@ -1,5 +1,5 @@
 #![doc = include_str!("../README.md")]
-use bdk_chain::{BlockId, ConfirmationTimeAnchor};
+use bdk_chain::ConfirmationTime;
 use esplora_client::TxStatus;

 pub use esplora_client;
@@ -14,16 +14,14 @@ mod async_ext;
 #[cfg(feature = "async")]
 pub use async_ext::*;

-pub(crate) fn map_confirmation_time_anchor(
+pub(crate) fn map_confirmation_time(
    tx_status: &TxStatus,
-    tip_at_start: BlockId,
-) -> Option<ConfirmationTimeAnchor> {
+    height_at_start: u32,
+) -> ConfirmationTime {
    match (tx_status.block_time, tx_status.block_height) {
-        (Some(confirmation_time), Some(confirmation_height)) => Some(ConfirmationTimeAnchor {
-            anchor_block: tip_at_start,
-            confirmation_height,
-            confirmation_time,
-        }),
-        _ => None,
+        (Some(time), Some(height)) if height <= height_at_start => {
+            ConfirmationTime::Confirmed { height, time }
+        }
+        _ => ConfirmationTime::Unconfirmed,
    }
 }
--- a/crates/file_store/Cargo.toml
+++ b/crates/file_store/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "bdk_file_store"
-version = "0.2.0"
+version = "0.1.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/bitcoindevkit/bdk"
@@ -11,7 +11,7 @@ authors = ["Bitcoin Dev Kit Developers"]
 readme = "README.md"

 [dependencies]
-bdk_chain = { path = "../chain", version = "0.5.0", features = [ "serde", "miniscript" ] }
+bdk_chain = { path = "../chain", version = "0.4.0", features = [ "serde", "miniscript" ] }
 bincode = { version = "1" }
 serde = { version = "1", features = ["derive"] }

--- a/crates/file_store/README.md
+++ b/crates/file_store/README.md
@@ -1,9 +1,9 @@
 # BDK File Store

 This is a simple append-only flat file implementation of
-[`Persist`](`bdk_chain::Persist`).
+[`Persist`](`bdk_chain::keychain::persist::Persist`).

-The main structure is [`Store`](`crate::Store`), which can be used with [`bdk`]'s
+The main structure is [`KeychainStore`](`crate::KeychainStore`), which can be used with [`bdk`]'s
 `Wallet` to persist wallet data into a flat file.

 [`bdk`]: https://docs.rs/bdk/latest
--- a/crates/file_store/src/entry_iter.rs
+++ b/crates/file_store/src/entry_iter.rs
@@ -1,100 +0,0 @@
-use bincode::Options;
-use std::{
-    fs::File,
-    io::{self, Seek},
-    marker::PhantomData,
-};
-
-use crate::bincode_options;
-
-/// Iterator over entries in a file store.
-///
-/// Reads and returns an entry each time [`next`] is called. If an error occurs while reading the
-/// iterator will yield a `Result::Err(_)` instead and then `None` for the next call to `next`.
-///
-/// [`next`]: Self::next
-pub struct EntryIter<'t, T> {
-    db_file: Option<&'t mut File>,
-
-    /// The file position for the first read of `db_file`.
-    start_pos: Option<u64>,
-    types: PhantomData<T>,
-}
-
-impl<'t, T> EntryIter<'t, T> {
-    pub fn new(start_pos: u64, db_file: &'t mut File) -> Self {
-        Self {
-            db_file: Some(db_file),
-            start_pos: Some(start_pos),
-            types: PhantomData,
-        }
-    }
-}
-
-impl<'t, T> Iterator for EntryIter<'t, T>
-where
-    T: serde::de::DeserializeOwned,
-{
-    type Item = Result<T, IterError>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        // closure which reads a single entry starting from `self.pos`
-        let read_one = |f: &mut File, start_pos: Option<u64>| -> Result<Option<T>, IterError> {
-            let pos = match start_pos {
-                Some(pos) => f.seek(io::SeekFrom::Start(pos))?,
-                None => f.stream_position()?,
-            };
-
-            match bincode_options().deserialize_from(&*f) {
-                Ok(changeset) => {
-                    f.stream_position()?;
-                    Ok(Some(changeset))
-                }
-                Err(e) => {
-                    if let bincode::ErrorKind::Io(inner) = &*e {
-                        if inner.kind() == io::ErrorKind::UnexpectedEof {
-                            let eof = f.seek(io::SeekFrom::End(0))?;
-                            if pos == eof {
-                                return Ok(None);
-                            }
-                        }
-                    }
-                    f.seek(io::SeekFrom::Start(pos))?;
-                    Err(IterError::Bincode(*e))
-                }
-            }
-        };
-
-        let result = read_one(self.db_file.as_mut()?, self.start_pos.take());
-        if result.is_err() {
-            self.db_file = None;
-        }
-        result.transpose()
-    }
-}
-
-impl From<io::Error> for IterError {
-    fn from(value: io::Error) -> Self {
-        IterError::Io(value)
-    }
-}
-
-/// Error type for [`EntryIter`].
-#[derive(Debug)]
-pub enum IterError {
-    /// Failure to read from the file.
-    Io(io::Error),
-    /// Failure to decode data from the file.
-    Bincode(bincode::ErrorKind),
-}
-
-impl core::fmt::Display for IterError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            IterError::Io(e) => write!(f, "io error trying to read entry {}", e),
-            IterError::Bincode(e) => write!(f, "bincode error while reading entry {}", e),
-        }
-    }
-}
-
-impl std::error::Error for IterError {}
--- a/crates/file_store/src/file_store.rs
+++ b/crates/file_store/src/file_store.rs
@@ -0,0 +1,404 @@
+//! Module for persisting data on disk.
+//!
+//! The star of the show is [`KeychainStore`], which maintains an append-only file of
+//! [`KeychainChangeSet`]s which can be used to restore a [`KeychainTracker`].
+use bdk_chain::{
+    keychain::{KeychainChangeSet, KeychainTracker},
+    sparse_chain,
+};
+use bincode::{DefaultOptions, Options};
+use core::marker::PhantomData;
+use std::{
+    fs::{File, OpenOptions},
+    io::{self, Read, Seek, Write},
+    path::Path,
+};
+
+/// BDK File Store magic bytes length.
+const MAGIC_BYTES_LEN: usize = 12;
+
+/// BDK File Store magic bytes.
+const MAGIC_BYTES: [u8; MAGIC_BYTES_LEN] = [98, 100, 107, 102, 115, 48, 48, 48, 48, 48, 48, 48];
+
+/// Persists an append only list of `KeychainChangeSet<K,P>` to a single file.
+/// [`KeychainChangeSet<K,P>`] record the changes made to a [`KeychainTracker<K,P>`].
+#[derive(Debug)]
+pub struct KeychainStore<K, P> {
+    db_file: File,
+    changeset_type_params: core::marker::PhantomData<(K, P)>,
+}
+
+fn bincode() -> impl bincode::Options {
+    DefaultOptions::new().with_varint_encoding()
+}
+
+impl<K, P> KeychainStore<K, P>
+where
+    K: Ord + Clone + core::fmt::Debug,
+    P: sparse_chain::ChainPosition,
+    KeychainChangeSet<K, P>: serde::Serialize + serde::de::DeserializeOwned,
+{
+    /// Creates a new store from a [`File`].
+    ///
+    /// The file must have been opened with read and write permissions.
+    ///
+    /// [`File`]: std::fs::File
+    pub fn new(mut file: File) -> Result<Self, FileError> {
+        file.rewind()?;
+
+        let mut magic_bytes = [0_u8; MAGIC_BYTES_LEN];
+        file.read_exact(&mut magic_bytes)?;
+
+        if magic_bytes != MAGIC_BYTES {
+            return Err(FileError::InvalidMagicBytes(magic_bytes));
+        }
+
+        Ok(Self {
+            db_file: file,
+            changeset_type_params: Default::default(),
+        })
+    }
+
+    /// Creates or loads a store from `db_path`. If no file exists there, it will be created.
+    pub fn new_from_path<D: AsRef<Path>>(db_path: D) -> Result<Self, FileError> {
+        let already_exists = db_path.as_ref().exists();
+
+        let mut db_file = OpenOptions::new()
+            .read(true)
+            .write(true)
+            .create(true)
+            .open(db_path)?;
+
+        if !already_exists {
+            db_file.write_all(&MAGIC_BYTES)?;
+        }
+
+        Self::new(db_file)
+    }
+
+    /// Iterates over the stored changeset from first to last, changing the seek position at each
+    /// iteration.
+    ///
+    /// The iterator may fail to read an entry and therefore return an error. However, the first time
+    /// it returns an error will be the last. After doing so, the iterator will always yield `None`.
+    ///
+    /// **WARNING**: This method changes the write position in the underlying file. You should
+    /// always iterate over all entries until `None` is returned if you want your next write to go
+    /// at the end; otherwise, you will write over existing entries.
+    pub fn iter_changesets(&mut self) -> Result<EntryIter<'_, KeychainChangeSet<K, P>>, io::Error> {
+        self.db_file
+            .seek(io::SeekFrom::Start(MAGIC_BYTES_LEN as _))?;
+
+        Ok(EntryIter::new(&mut self.db_file))
+    }
+
+    /// Loads all the changesets that have been stored as one giant changeset.
+    ///
+    /// This function returns a tuple of the aggregate changeset and a result that indicates
+    /// whether an error occurred while reading or deserializing one of the entries. If so the
+    /// changeset will consist of all of those it was able to read.
+    ///
+    /// You should usually check the error. In many applications, it may make sense to do a full
+    /// wallet scan with a stop-gap after getting an error, since it is likely that one of the
+    /// changesets it was unable to read changed the derivation indices of the tracker.
+    ///
+    /// **WARNING**: This method changes the write position of the underlying file. The next
+    /// changeset will be written over the erroring entry (or the end of the file if none existed).
+    pub fn aggregate_changeset(&mut self) -> (KeychainChangeSet<K, P>, Result<(), IterError>) {
+        let mut changeset = KeychainChangeSet::default();
+        let result = (|| {
+            let iter_changeset = self.iter_changesets()?;
+            for next_changeset in iter_changeset {
+                changeset.append(next_changeset?);
+            }
+            Ok(())
+        })();
+
+        (changeset, result)
+    }
+
+    /// Reads and applies all the changesets stored sequentially to the tracker, stopping when it fails
+    /// to read the next one.
+    ///
+    /// **WARNING**: This method changes the write position of the underlying file. The next
+    /// changeset will be written over the erroring entry (or the end of the file if none existed).
+    pub fn load_into_keychain_tracker(
+        &mut self,
+        tracker: &mut KeychainTracker<K, P>,
+    ) -> Result<(), IterError> {
+        for changeset in self.iter_changesets()? {
+            tracker.apply_changeset(changeset?)
+        }
+        Ok(())
+    }
+
+    /// Append a new changeset to the file and truncate the file to the end of the appended changeset.
+    ///
+    /// The truncation is to avoid the possibility of having a valid but inconsistent changeset
+    /// directly after the appended changeset.
+    pub fn append_changeset(
+        &mut self,
+        changeset: &KeychainChangeSet<K, P>,
+    ) -> Result<(), io::Error> {
+        if changeset.is_empty() {
+            return Ok(());
+        }
+
+        bincode()
+            .serialize_into(&mut self.db_file, changeset)
+            .map_err(|e| match *e {
+                bincode::ErrorKind::Io(inner) => inner,
+                unexpected_err => panic!("unexpected bincode error: {}", unexpected_err),
+            })?;
+
+        // truncate file after this changeset addition
+        // if this is not done, data after this changeset may represent valid changesets, however
+        // applying those changesets on top of this one may result in an inconsistent state
+        let pos = self.db_file.stream_position()?;
+        self.db_file.set_len(pos)?;
+
+        // We want to make sure that derivation indices changes are written to disk as soon as
+        // possible, so you know about the write failure before you give out the address in the application.
+        if !changeset.derivation_indices.is_empty() {
+            self.db_file.sync_data()?;
+        }
+
+        Ok(())
+    }
+}
+
+/// Error that occurs due to problems encountered with the file.
+#[derive(Debug)]
+pub enum FileError {
+    /// IO error, this may mean that the file is too short.
+    Io(io::Error),
+    /// Magic bytes do not match what is expected.
+    InvalidMagicBytes([u8; MAGIC_BYTES_LEN]),
+}
+
+impl core::fmt::Display for FileError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self {
+            Self::Io(e) => write!(f, "io error trying to read file: {}", e),
+            Self::InvalidMagicBytes(b) => write!(
+                f,
+                "file has invalid magic bytes: expected={:?} got={:?}",
+                MAGIC_BYTES, b
+            ),
+        }
+    }
+}
+
+impl From<io::Error> for FileError {
+    fn from(value: io::Error) -> Self {
+        Self::Io(value)
+    }
+}
+
+impl std::error::Error for FileError {}
+
+/// Error type for [`EntryIter`].
+#[derive(Debug)]
+pub enum IterError {
+    /// Failure to read from the file.
+    Io(io::Error),
+    /// Failure to decode data from the file.
+    Bincode(bincode::ErrorKind),
+}
+
+impl core::fmt::Display for IterError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self {
+            IterError::Io(e) => write!(f, "io error trying to read entry {}", e),
+            IterError::Bincode(e) => write!(f, "bincode error while reading entry {}", e),
+        }
+    }
+}
+
+impl std::error::Error for IterError {}
+
+/// Iterator over entries in a file store.
+///
+/// Reads and returns an entry each time [`next`] is called. If an error occurs while reading the
+/// iterator will yield a `Result::Err(_)` instead and then `None` for the next call to `next`.
+///
+/// [`next`]: Self::next
+pub struct EntryIter<'a, V> {
+    db_file: &'a mut File,
+    types: PhantomData<V>,
+    error_exit: bool,
+}
+
+impl<'a, V> EntryIter<'a, V> {
+    pub fn new(db_file: &'a mut File) -> Self {
+        Self {
+            db_file,
+            types: PhantomData,
+            error_exit: false,
+        }
+    }
+}
+
+impl<'a, V> Iterator for EntryIter<'a, V>
+where
+    V: serde::de::DeserializeOwned,
+{
+    type Item = Result<V, IterError>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let result = (|| {
+            let pos = self.db_file.stream_position()?;
+
+            match bincode().deserialize_from(&mut self.db_file) {
+                Ok(changeset) => Ok(Some(changeset)),
+                Err(e) => {
+                    if let bincode::ErrorKind::Io(inner) = &*e {
+                        if inner.kind() == io::ErrorKind::UnexpectedEof {
+                            let eof = self.db_file.seek(io::SeekFrom::End(0))?;
+                            if pos == eof {
+                                return Ok(None);
+                            }
+                        }
+                    }
+
+                    self.db_file.seek(io::SeekFrom::Start(pos))?;
+                    Err(IterError::Bincode(*e))
+                }
+            }
+        })();
+
+        let result = result.transpose();
+
+        if let Some(Err(_)) = &result {
+            self.error_exit = true;
+        }
+
+        result
+    }
+}
+
+impl From<io::Error> for IterError {
+    fn from(value: io::Error) -> Self {
+        IterError::Io(value)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use bdk_chain::{
+        keychain::{DerivationAdditions, KeychainChangeSet},
+        TxHeight,
+    };
+    use std::{
+        io::{Read, Write},
+        vec::Vec,
+    };
+    use tempfile::NamedTempFile;
+    #[derive(
+        Debug,
+        Clone,
+        Copy,
+        PartialOrd,
+        Ord,
+        PartialEq,
+        Eq,
+        Hash,
+        serde::Serialize,
+        serde::Deserialize,
+    )]
+    enum TestKeychain {
+        External,
+        Internal,
+    }
+
+    impl core::fmt::Display for TestKeychain {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            match self {
+                Self::External => write!(f, "external"),
+                Self::Internal => write!(f, "internal"),
+            }
+        }
+    }
+
+    #[test]
+    fn magic_bytes() {
+        assert_eq!(&MAGIC_BYTES, "bdkfs0000000".as_bytes());
+    }
+
+    #[test]
+    fn new_fails_if_file_is_too_short() {
+        let mut file = NamedTempFile::new().unwrap();
+        file.write_all(&MAGIC_BYTES[..MAGIC_BYTES_LEN - 1])
+            .expect("should write");
+
+        match KeychainStore::<TestKeychain, TxHeight>::new(file.reopen().unwrap()) {
+            Err(FileError::Io(e)) => assert_eq!(e.kind(), std::io::ErrorKind::UnexpectedEof),
+            unexpected => panic!("unexpected result: {:?}", unexpected),
+        };
+    }
+
+    #[test]
+    fn new_fails_if_magic_bytes_are_invalid() {
+        let invalid_magic_bytes = "ldkfs0000000";
+
+        let mut file = NamedTempFile::new().unwrap();
+        file.write_all(invalid_magic_bytes.as_bytes())
+            .expect("should write");
+
+        match KeychainStore::<TestKeychain, TxHeight>::new(file.reopen().unwrap()) {
+            Err(FileError::InvalidMagicBytes(b)) => {
+                assert_eq!(b, invalid_magic_bytes.as_bytes())
+            }
+            unexpected => panic!("unexpected result: {:?}", unexpected),
+        };
+    }
+
+    #[test]
+    fn append_changeset_truncates_invalid_bytes() {
+        // initial data to write to file (magic bytes + invalid data)
+        let mut data = [255_u8; 2000];
+        data[..MAGIC_BYTES_LEN].copy_from_slice(&MAGIC_BYTES);
+
+        let changeset = KeychainChangeSet {
+            derivation_indices: DerivationAdditions(
+                vec![(TestKeychain::External, 42)].into_iter().collect(),
+            ),
+            chain_graph: Default::default(),
+        };
+
+        let mut file = NamedTempFile::new().unwrap();
+        file.write_all(&data).expect("should write");
+
+        let mut store = KeychainStore::<TestKeychain, TxHeight>::new(file.reopen().unwrap())
+            .expect("should open");
+        match store.iter_changesets().expect("seek should succeed").next() {
+            Some(Err(IterError::Bincode(_))) => {}
+            unexpected_res => panic!("unexpected result: {:?}", unexpected_res),
+        }
+
+        store.append_changeset(&changeset).expect("should append");
+
+        drop(store);
+
+        let got_bytes = {
+            let mut buf = Vec::new();
+            file.reopen()
+                .unwrap()
+                .read_to_end(&mut buf)
+                .expect("should read");
+            buf
+        };
+
+        let expected_bytes = {
+            let mut buf = MAGIC_BYTES.to_vec();
+            DefaultOptions::new()
+                .with_varint_encoding()
+                .serialize_into(&mut buf, &changeset)
+                .expect("should encode");
+            buf
+        };
+
+        assert_eq!(got_bytes, expected_bytes);
+    }
+}
--- a/crates/file_store/src/lib.rs
+++ b/crates/file_store/src/lib.rs
@@ -1,42 +1,32 @@
 #![doc = include_str!("../README.md")]
-mod entry_iter;
-mod store;
-use std::io;
+mod file_store;
+use bdk_chain::{
+    keychain::{KeychainChangeSet, KeychainTracker, PersistBackend},
+    sparse_chain::ChainPosition,
+};
+pub use file_store::*;

-use bincode::{DefaultOptions, Options};
-pub use entry_iter::*;
-pub use store::*;
+impl<K, P> PersistBackend<K, P> for KeychainStore<K, P>
+where
+    K: Ord + Clone + core::fmt::Debug,
+    P: ChainPosition,
+    KeychainChangeSet<K, P>: serde::Serialize + serde::de::DeserializeOwned,
+{
+    type WriteError = std::io::Error;

-pub(crate) fn bincode_options() -> impl bincode::Options {
-    DefaultOptions::new().with_varint_encoding()
-}
+    type LoadError = IterError;

-/// Error that occurs due to problems encountered with the file.
-#[derive(Debug)]
-pub enum FileError<'a> {
-    /// IO error, this may mean that the file is too short.
-    Io(io::Error),
-    /// Magic bytes do not match what is expected.
-    InvalidMagicBytes { got: Vec<u8>, expected: &'a [u8] },
-}
+    fn append_changeset(
+        &mut self,
+        changeset: &KeychainChangeSet<K, P>,
+    ) -> Result<(), Self::WriteError> {
+        KeychainStore::append_changeset(self, changeset)
+    }

-impl<'a> core::fmt::Display for FileError<'a> {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            Self::Io(e) => write!(f, "io error trying to read file: {}", e),
-            Self::InvalidMagicBytes { got, expected } => write!(
-                f,
-                "file has invalid magic bytes: expected={:?} got={:?}",
-                expected, got,
-            ),
-        }
+    fn load_into_keychain_tracker(
+        &mut self,
+        tracker: &mut KeychainTracker<K, P>,
+    ) -> Result<(), Self::LoadError> {
+        KeychainStore::load_into_keychain_tracker(self, tracker)
    }
 }
-
-impl<'a> From<io::Error> for FileError<'a> {
-    fn from(value: io::Error) -> Self {
-        Self::Io(value)
-    }
-}
-
-impl<'a> std::error::Error for FileError<'a> {}
--- a/crates/file_store/src/store.rs
+++ b/crates/file_store/src/store.rs
@@ -1,255 +0,0 @@
-use std::{
-    fmt::Debug,
-    fs::{File, OpenOptions},
-    io::{self, Read, Seek, Write},
-    marker::PhantomData,
-    path::Path,
-};
-
-use bdk_chain::{Append, PersistBackend};
-use bincode::Options;
-
-use crate::{bincode_options, EntryIter, FileError, IterError};
-
-/// Persists an append-only list of changesets (`C`) to a single file.
-///
-/// The changesets are the results of altering a tracker implementation (`T`).
-#[derive(Debug)]
-pub struct Store<'a, C> {
-    magic: &'a [u8],
-    db_file: File,
-    marker: PhantomData<C>,
-}
-
-impl<'a, C> PersistBackend<C> for Store<'a, C>
-where
-    C: Default + Append + serde::Serialize + serde::de::DeserializeOwned,
-{
-    type WriteError = std::io::Error;
-
-    type LoadError = IterError;
-
-    fn write_changes(&mut self, changeset: &C) -> Result<(), Self::WriteError> {
-        self.append_changeset(changeset)
-    }
-
-    fn load_from_persistence(&mut self) -> Result<C, Self::LoadError> {
-        let (changeset, result) = self.aggregate_changesets();
-        result.map(|_| changeset)
-    }
-}
-
-impl<'a, C> Store<'a, C>
-where
-    C: Default + Append + serde::Serialize + serde::de::DeserializeOwned,
-{
-    /// Creates a new store from a [`File`].
-    ///
-    /// The file must have been opened with read and write permissions.
-    ///
-    /// `magic` is the expected prefixed bytes of the file. If this does not match, an error will be
-    /// returned.
-    ///
-    /// [`File`]: std::fs::File
-    pub fn new(magic: &'a [u8], mut db_file: File) -> Result<Self, FileError> {
-        db_file.rewind()?;
-
-        let mut magic_buf = vec![0_u8; magic.len()];
-        db_file.read_exact(magic_buf.as_mut())?;
-
-        if magic_buf != magic {
-            return Err(FileError::InvalidMagicBytes {
-                got: magic_buf,
-                expected: magic,
-            });
-        }
-
-        Ok(Self {
-            magic,
-            db_file,
-            marker: Default::default(),
-        })
-    }
-
-    /// Creates or loads a store from `db_path`.
-    ///
-    /// If no file exists there, it will be created.
-    ///
-    /// Refer to [`new`] for documentation on the `magic` input.
-    ///
-    /// [`new`]: Self::new
-    pub fn new_from_path<P>(magic: &'a [u8], db_path: P) -> Result<Self, FileError>
-    where
-        P: AsRef<Path>,
-    {
-        let already_exists = db_path.as_ref().exists();
-
-        let mut db_file = OpenOptions::new()
-            .read(true)
-            .write(true)
-            .create(true)
-            .open(db_path)?;
-
-        if !already_exists {
-            db_file.write_all(magic)?;
-        }
-
-        Self::new(magic, db_file)
-    }
-
-    /// Iterates over the stored changeset from first to last, changing the seek position at each
-    /// iteration.
-    ///
-    /// The iterator may fail to read an entry and therefore return an error. However, the first time
-    /// it returns an error will be the last. After doing so, the iterator will always yield `None`.
-    ///
-    /// **WARNING**: This method changes the write position in the underlying file. You should
-    /// always iterate over all entries until `None` is returned if you want your next write to go
-    /// at the end; otherwise, you will write over existing entries.
-    pub fn iter_changesets(&mut self) -> EntryIter<C> {
-        EntryIter::new(self.magic.len() as u64, &mut self.db_file)
-    }
-
-    /// Loads all the changesets that have been stored as one giant changeset.
-    ///
-    /// This function returns a tuple of the aggregate changeset and a result that indicates
-    /// whether an error occurred while reading or deserializing one of the entries. If so the
-    /// changeset will consist of all of those it was able to read.
-    ///
-    /// You should usually check the error. In many applications, it may make sense to do a full
-    /// wallet scan with a stop-gap after getting an error, since it is likely that one of the
-    /// changesets it was unable to read changed the derivation indices of the tracker.
-    ///
-    /// **WARNING**: This method changes the write position of the underlying file. The next
-    /// changeset will be written over the erroring entry (or the end of the file if none existed).
-    pub fn aggregate_changesets(&mut self) -> (C, Result<(), IterError>) {
-        let mut changeset = C::default();
-        let result = (|| {
-            for next_changeset in self.iter_changesets() {
-                changeset.append(next_changeset?);
-            }
-            Ok(())
-        })();
-
-        (changeset, result)
-    }
-
-    /// Append a new changeset to the file and truncate the file to the end of the appended
-    /// changeset.
-    ///
-    /// The truncation is to avoid the possibility of having a valid but inconsistent changeset
-    /// directly after the appended changeset.
-    pub fn append_changeset(&mut self, changeset: &C) -> Result<(), io::Error> {
-        // no need to write anything if changeset is empty
-        if changeset.is_empty() {
-            return Ok(());
-        }
-
-        bincode_options()
-            .serialize_into(&mut self.db_file, changeset)
-            .map_err(|e| match *e {
-                bincode::ErrorKind::Io(inner) => inner,
-                unexpected_err => panic!("unexpected bincode error: {}", unexpected_err),
-            })?;
-
-        // truncate file after this changeset addition
-        // if this is not done, data after this changeset may represent valid changesets, however
-        // applying those changesets on top of this one may result in an inconsistent state
-        let pos = self.db_file.stream_position()?;
-        self.db_file.set_len(pos)?;
-
-        Ok(())
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    use bincode::DefaultOptions;
-    use std::{
-        io::{Read, Write},
-        vec::Vec,
-    };
-    use tempfile::NamedTempFile;
-
-    const TEST_MAGIC_BYTES_LEN: usize = 12;
-    const TEST_MAGIC_BYTES: [u8; TEST_MAGIC_BYTES_LEN] =
-        [98, 100, 107, 102, 115, 49, 49, 49, 49, 49, 49, 49];
-
-    type TestChangeSet = Vec<String>;
-
-    #[derive(Debug)]
-    struct TestTracker;
-
-    #[test]
-    fn new_fails_if_file_is_too_short() {
-        let mut file = NamedTempFile::new().unwrap();
-        file.write_all(&TEST_MAGIC_BYTES[..TEST_MAGIC_BYTES_LEN - 1])
-            .expect("should write");
-
-        match Store::<TestChangeSet>::new(&TEST_MAGIC_BYTES, file.reopen().unwrap()) {
-            Err(FileError::Io(e)) => assert_eq!(e.kind(), std::io::ErrorKind::UnexpectedEof),
-            unexpected => panic!("unexpected result: {:?}", unexpected),
-        };
-    }
-
-    #[test]
-    fn new_fails_if_magic_bytes_are_invalid() {
-        let invalid_magic_bytes = "ldkfs0000000";
-
-        let mut file = NamedTempFile::new().unwrap();
-        file.write_all(invalid_magic_bytes.as_bytes())
-            .expect("should write");
-
-        match Store::<TestChangeSet>::new(&TEST_MAGIC_BYTES, file.reopen().unwrap()) {
-            Err(FileError::InvalidMagicBytes { got, .. }) => {
-                assert_eq!(got, invalid_magic_bytes.as_bytes())
-            }
-            unexpected => panic!("unexpected result: {:?}", unexpected),
-        };
-    }
-
-    #[test]
-    fn append_changeset_truncates_invalid_bytes() {
-        // initial data to write to file (magic bytes + invalid data)
-        let mut data = [255_u8; 2000];
-        data[..TEST_MAGIC_BYTES_LEN].copy_from_slice(&TEST_MAGIC_BYTES);
-
-        let changeset = vec!["one".into(), "two".into(), "three!".into()];
-
-        let mut file = NamedTempFile::new().unwrap();
-        file.write_all(&data).expect("should write");
-
-        let mut store = Store::<TestChangeSet>::new(&TEST_MAGIC_BYTES, file.reopen().unwrap())
-            .expect("should open");
-        match store.iter_changesets().next() {
-            Some(Err(IterError::Bincode(_))) => {}
-            unexpected_res => panic!("unexpected result: {:?}", unexpected_res),
-        }
-
-        store.append_changeset(&changeset).expect("should append");
-
-        drop(store);
-
-        let got_bytes = {
-            let mut buf = Vec::new();
-            file.reopen()
-                .unwrap()
-                .read_to_end(&mut buf)
-                .expect("should read");
-            buf
-        };
-
-        let expected_bytes = {
-            let mut buf = TEST_MAGIC_BYTES.to_vec();
-            DefaultOptions::new()
-                .with_varint_encoding()
-                .serialize_into(&mut buf, &changeset)
-                .expect("should encode");
-            buf
-        };
-
-        assert_eq!(got_bytes, expected_bytes);
-    }
-}
--- a/example-crates/example_cli/src/lib.rs
+++ b/example-crates/example_cli/src/lib.rs
@@ -1,736 +0,0 @@
-pub use anyhow;
-use anyhow::Context;
-use bdk_coin_select::{coin_select_bnb, CoinSelector, CoinSelectorOpt, WeightedValue};
-use bdk_file_store::Store;
-use serde::{de::DeserializeOwned, Serialize};
-use std::{cmp::Reverse, collections::HashMap, path::PathBuf, sync::Mutex, time::Duration};
-
-use bdk_chain::{
-    bitcoin::{
-        psbt::Prevouts, secp256k1::Secp256k1, util::sighash::SighashCache, Address, LockTime,
-        Network, Sequence, Transaction, TxIn, TxOut,
-    },
-    indexed_tx_graph::{IndexedAdditions, IndexedTxGraph},
-    keychain::{DerivationAdditions, KeychainTxOutIndex},
-    miniscript::{
-        descriptor::{DescriptorSecretKey, KeyMap},
-        Descriptor, DescriptorPublicKey,
-    },
-    Anchor, Append, ChainOracle, DescriptorExt, FullTxOut, Persist, PersistBackend,
-};
-pub use bdk_file_store;
-pub use clap;
-
-use clap::{Parser, Subcommand};
-
-pub type KeychainTxGraph<A> = IndexedTxGraph<A, KeychainTxOutIndex<Keychain>>;
-pub type KeychainAdditions<A> = IndexedAdditions<A, DerivationAdditions<Keychain>>;
-pub type Database<'m, C> = Persist<Store<'m, C>, C>;
-
-#[derive(Parser)]
-#[clap(author, version, about, long_about = None)]
-#[clap(propagate_version = true)]
-pub struct Args<S: clap::Subcommand> {
-    #[clap(env = "DESCRIPTOR")]
-    pub descriptor: String,
-    #[clap(env = "CHANGE_DESCRIPTOR")]
-    pub change_descriptor: Option<String>,
-
-    #[clap(env = "BITCOIN_NETWORK", long, default_value = "signet")]
-    pub network: Network,
-
-    #[clap(env = "BDK_DB_PATH", long, default_value = ".bdk_example_db")]
-    pub db_path: PathBuf,
-
-    #[clap(env = "BDK_CP_LIMIT", long, default_value = "20")]
-    pub cp_limit: usize,
-
-    #[clap(subcommand)]
-    pub command: Commands<S>,
-}
-
-#[allow(clippy::almost_swapped)]
-#[derive(Subcommand, Debug, Clone)]
-pub enum Commands<S: clap::Subcommand> {
-    #[clap(flatten)]
-    ChainSpecific(S),
-    /// Address generation and inspection.
-    Address {
-        #[clap(subcommand)]
-        addr_cmd: AddressCmd,
-    },
-    /// Get the wallet balance.
-    Balance,
-    /// TxOut related commands.
-    #[clap(name = "txout")]
-    TxOut {
-        #[clap(subcommand)]
-        txout_cmd: TxOutCmd,
-    },
-    /// Send coins to an address.
-    Send {
-        value: u64,
-        address: Address,
-        #[clap(short, default_value = "bnb")]
-        coin_select: CoinSelectionAlgo,
-    },
-}
-
-#[derive(Clone, Debug)]
-pub enum CoinSelectionAlgo {
-    LargestFirst,
-    SmallestFirst,
-    OldestFirst,
-    NewestFirst,
-    BranchAndBound,
-}
-
-impl Default for CoinSelectionAlgo {
-    fn default() -> Self {
-        Self::LargestFirst
-    }
-}
-
-impl core::str::FromStr for CoinSelectionAlgo {
-    type Err = anyhow::Error;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        use CoinSelectionAlgo::*;
-        Ok(match s {
-            "largest-first" => LargestFirst,
-            "smallest-first" => SmallestFirst,
-            "oldest-first" => OldestFirst,
-            "newest-first" => NewestFirst,
-            "bnb" => BranchAndBound,
-            unknown => {
-                return Err(anyhow::anyhow!(
-                    "unknown coin selection algorithm '{}'",
-                    unknown
-                ))
-            }
-        })
-    }
-}
-
-impl core::fmt::Display for CoinSelectionAlgo {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        use CoinSelectionAlgo::*;
-        write!(
-            f,
-            "{}",
-            match self {
-                LargestFirst => "largest-first",
-                SmallestFirst => "smallest-first",
-                OldestFirst => "oldest-first",
-                NewestFirst => "newest-first",
-                BranchAndBound => "bnb",
-            }
-        )
-    }
-}
-
-#[allow(clippy::almost_swapped)]
-#[derive(Subcommand, Debug, Clone)]
-pub enum AddressCmd {
-    /// Get the next unused address.
-    Next,
-    /// Get a new address regardless of the existing unused addresses.
-    New,
-    /// List all addresses
-    List {
-        #[clap(long)]
-        change: bool,
-    },
-    Index,
-}
-
-#[derive(Subcommand, Debug, Clone)]
-pub enum TxOutCmd {
-    List {
-        /// Return only spent outputs.
-        #[clap(short, long)]
-        spent: bool,
-        /// Return only unspent outputs.
-        #[clap(short, long)]
-        unspent: bool,
-        /// Return only confirmed outputs.
-        #[clap(long)]
-        confirmed: bool,
-        /// Return only unconfirmed outputs.
-        #[clap(long)]
-        unconfirmed: bool,
-    },
-}
-
-#[derive(
-    Debug, Clone, Copy, PartialOrd, Ord, PartialEq, Eq, serde::Deserialize, serde::Serialize,
-)]
-pub enum Keychain {
-    External,
-    Internal,
-}
-
-impl core::fmt::Display for Keychain {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            Keychain::External => write!(f, "external"),
-            Keychain::Internal => write!(f, "internal"),
-        }
-    }
-}
-
-pub fn run_address_cmd<A, C>(
-    graph: &mut KeychainTxGraph<A>,
-    db: &Mutex<Database<C>>,
-    network: Network,
-    cmd: AddressCmd,
-) -> anyhow::Result<()>
-where
-    C: Default + Append + DeserializeOwned + Serialize + From<KeychainAdditions<A>>,
-{
-    let index = &mut graph.index;
-
-    match cmd {
-        AddressCmd::Next | AddressCmd::New => {
-            let spk_chooser = match cmd {
-                AddressCmd::Next => KeychainTxOutIndex::next_unused_spk,
-                AddressCmd::New => KeychainTxOutIndex::reveal_next_spk,
-                _ => unreachable!("only these two variants exist in match arm"),
-            };
-
-            let ((spk_i, spk), index_additions) = spk_chooser(index, &Keychain::External);
-            let db = &mut *db.lock().unwrap();
-            db.stage(C::from(KeychainAdditions::from(index_additions)));
-            db.commit()?;
-            let addr = Address::from_script(spk, network).context("failed to derive address")?;
-            println!("[address @ {}] {}", spk_i, addr);
-            Ok(())
-        }
-        AddressCmd::Index => {
-            for (keychain, derivation_index) in index.last_revealed_indices() {
-                println!("{:?}: {}", keychain, derivation_index);
-            }
-            Ok(())
-        }
-        AddressCmd::List { change } => {
-            let target_keychain = match change {
-                true => Keychain::Internal,
-                false => Keychain::External,
-            };
-            for (spk_i, spk) in index.revealed_spks_of_keychain(&target_keychain) {
-                let address = Address::from_script(spk, network)
-                    .expect("should always be able to derive address");
-                println!(
-                    "{:?} {} used:{}",
-                    spk_i,
-                    address,
-                    index.is_used(&(target_keychain, spk_i))
-                );
-            }
-            Ok(())
-        }
-    }
-}
-
-pub fn run_balance_cmd<A: Anchor, O: ChainOracle>(
-    graph: &KeychainTxGraph<A>,
-    chain: &O,
-) -> Result<(), O::Error> {
-    fn print_balances<'a>(title_str: &'a str, items: impl IntoIterator<Item = (&'a str, u64)>) {
-        println!("{}:", title_str);
-        for (name, amount) in items.into_iter() {
-            println!("    {:<10} {:>12} sats", name, amount)
-        }
-    }
-
-    let balance = graph.graph().try_balance(
-        chain,
-        chain.get_chain_tip()?.unwrap_or_default(),
-        graph.index.outpoints().iter().cloned(),
-        |(k, _), _| k == &Keychain::Internal,
-    )?;
-
-    let confirmed_total = balance.confirmed + balance.immature;
-    let unconfirmed_total = balance.untrusted_pending + balance.trusted_pending;
-
-    print_balances(
-        "confirmed",
-        [
-            ("total", confirmed_total),
-            ("spendable", balance.confirmed),
-            ("immature", balance.immature),
-        ],
-    );
-    print_balances(
-        "unconfirmed",
-        [
-            ("total", unconfirmed_total),
-            ("trusted", balance.trusted_pending),
-            ("untrusted", balance.untrusted_pending),
-        ],
-    );
-
-    Ok(())
-}
-
-pub fn run_txo_cmd<A: Anchor, O: ChainOracle>(
-    graph: &KeychainTxGraph<A>,
-    chain: &O,
-    network: Network,
-    cmd: TxOutCmd,
-) -> anyhow::Result<()>
-where
-    O::Error: std::error::Error + Send + Sync + 'static,
-{
-    let chain_tip = chain.get_chain_tip()?.unwrap_or_default();
-    let outpoints = graph.index.outpoints().iter().cloned();
-
-    match cmd {
-        TxOutCmd::List {
-            spent,
-            unspent,
-            confirmed,
-            unconfirmed,
-        } => {
-            let txouts = graph
-                .graph()
-                .try_filter_chain_txouts(chain, chain_tip, outpoints)
-                .filter(|r| match r {
-                    Ok((_, full_txo)) => match (spent, unspent) {
-                        (true, false) => full_txo.spent_by.is_some(),
-                        (false, true) => full_txo.spent_by.is_none(),
-                        _ => true,
-                    },
-                    // always keep errored items
-                    Err(_) => true,
-                })
-                .filter(|r| match r {
-                    Ok((_, full_txo)) => match (confirmed, unconfirmed) {
-                        (true, false) => full_txo.chain_position.is_confirmed(),
-                        (false, true) => !full_txo.chain_position.is_confirmed(),
-                        _ => true,
-                    },
-                    // always keep errored items
-                    Err(_) => true,
-                })
-                .collect::<Result<Vec<_>, _>>()?;
-
-            for (spk_i, full_txo) in txouts {
-                let addr = Address::from_script(&full_txo.txout.script_pubkey, network)?;
-                println!(
-                    "{:?} {} {} {} spent:{:?}",
-                    spk_i, full_txo.txout.value, full_txo.outpoint, addr, full_txo.spent_by
-                )
-            }
-            Ok(())
-        }
-    }
-}
-
-#[allow(clippy::too_many_arguments)]
-pub fn run_send_cmd<A: Anchor, O: ChainOracle, C>(
-    graph: &Mutex<KeychainTxGraph<A>>,
-    db: &Mutex<Database<'_, C>>,
-    chain: &O,
-    keymap: &HashMap<DescriptorPublicKey, DescriptorSecretKey>,
-    cs_algorithm: CoinSelectionAlgo,
-    address: Address,
-    value: u64,
-    broadcast: impl FnOnce(&Transaction) -> anyhow::Result<()>,
-) -> anyhow::Result<()>
-where
-    O::Error: std::error::Error + Send + Sync + 'static,
-    C: Default + Append + DeserializeOwned + Serialize + From<KeychainAdditions<A>>,
-{
-    let (transaction, change_index) = {
-        let graph = &mut *graph.lock().unwrap();
-        // take mutable ref to construct tx -- it is only open for a short time while building it.
-        let (tx, change_info) = create_tx(graph, chain, keymap, cs_algorithm, address, value)?;
-
-        if let Some((index_additions, (change_keychain, index))) = change_info {
-            // We must first persist to disk the fact that we've got a new address from the
-            // change keychain so future scans will find the tx we're about to broadcast.
-            // If we're unable to persist this, then we don't want to broadcast.
-            {
-                let db = &mut *db.lock().unwrap();
-                db.stage(C::from(KeychainAdditions::from(index_additions)));
-                db.commit()?;
-            }
-
-            // We don't want other callers/threads to use this address while we're using it
-            // but we also don't want to scan the tx we just created because it's not
-            // technically in the blockchain yet.
-            graph.index.mark_used(&change_keychain, index);
-            (tx, Some((change_keychain, index)))
-        } else {
-            (tx, None)
-        }
-    };
-
-    match (broadcast)(&transaction) {
-        Ok(_) => {
-            println!("Broadcasted Tx : {}", transaction.txid());
-
-            let keychain_additions = graph.lock().unwrap().insert_tx(&transaction, None, None);
-
-            // We know the tx is at least unconfirmed now. Note if persisting here fails,
-            // it's not a big deal since we can always find it again form
-            // blockchain.
-            db.lock().unwrap().stage(C::from(keychain_additions));
-            Ok(())
-        }
-        Err(e) => {
-            if let Some((keychain, index)) = change_index {
-                // We failed to broadcast, so allow our change address to be used in the future
-                graph.lock().unwrap().index.unmark_used(&keychain, index);
-            }
-            Err(e)
-        }
-    }
-}
-
-#[allow(clippy::type_complexity)]
-pub fn create_tx<A: Anchor, O: ChainOracle>(
-    graph: &mut KeychainTxGraph<A>,
-    chain: &O,
-    keymap: &HashMap<DescriptorPublicKey, DescriptorSecretKey>,
-    cs_algorithm: CoinSelectionAlgo,
-    address: Address,
-    value: u64,
-) -> anyhow::Result<(
-    Transaction,
-    Option<(DerivationAdditions<Keychain>, (Keychain, u32))>,
-)>
-where
-    O::Error: std::error::Error + Send + Sync + 'static,
-{
-    let mut additions = DerivationAdditions::default();
-
-    let assets = bdk_tmp_plan::Assets {
-        keys: keymap.iter().map(|(pk, _)| pk.clone()).collect(),
-        ..Default::default()
-    };
-
-    // TODO use planning module
-    let mut candidates = planned_utxos(graph, chain, &assets)?;
-
-    // apply coin selection algorithm
-    match cs_algorithm {
-        CoinSelectionAlgo::LargestFirst => {
-            candidates.sort_by_key(|(_, utxo)| Reverse(utxo.txout.value))
-        }
-        CoinSelectionAlgo::SmallestFirst => candidates.sort_by_key(|(_, utxo)| utxo.txout.value),
-        CoinSelectionAlgo::OldestFirst => {
-            candidates.sort_by_key(|(_, utxo)| utxo.chain_position.clone())
-        }
-        CoinSelectionAlgo::NewestFirst => {
-            candidates.sort_by_key(|(_, utxo)| Reverse(utxo.chain_position.clone()))
-        }
-        CoinSelectionAlgo::BranchAndBound => {}
-    }
-
-    // turn the txos we chose into weight and value
-    let wv_candidates = candidates
-        .iter()
-        .map(|(plan, utxo)| {
-            WeightedValue::new(
-                utxo.txout.value,
-                plan.expected_weight() as _,
-                plan.witness_version().is_some(),
-            )
-        })
-        .collect();
-
-    let mut outputs = vec![TxOut {
-        value,
-        script_pubkey: address.script_pubkey(),
-    }];
-
-    let internal_keychain = if graph.index.keychains().get(&Keychain::Internal).is_some() {
-        Keychain::Internal
-    } else {
-        Keychain::External
-    };
-
-    let ((change_index, change_script), change_additions) =
-        graph.index.next_unused_spk(&internal_keychain);
-    additions.append(change_additions);
-
-    // Clone to drop the immutable reference.
-    let change_script = change_script.clone();
-
-    let change_plan = bdk_tmp_plan::plan_satisfaction(
-        &graph
-            .index
-            .keychains()
-            .get(&internal_keychain)
-            .expect("must exist")
-            .at_derivation_index(change_index),
-        &assets,
-    )
-    .expect("failed to obtain change plan");
-
-    let mut change_output = TxOut {
-        value: 0,
-        script_pubkey: change_script,
-    };
-
-    let cs_opts = CoinSelectorOpt {
-        target_feerate: 0.5,
-        min_drain_value: graph
-            .index
-            .keychains()
-            .get(&internal_keychain)
-            .expect("must exist")
-            .dust_value(),
-        ..CoinSelectorOpt::fund_outputs(
-            &outputs,
-            &change_output,
-            change_plan.expected_weight() as u32,
-        )
-    };
-
-    // TODO: How can we make it easy to shuffle in order of inputs and outputs here?
-    // apply coin selection by saying we need to fund these outputs
-    let mut coin_selector = CoinSelector::new(&wv_candidates, &cs_opts);
-
-    // just select coins in the order provided until we have enough
-    // only use the first result (least waste)
-    let selection = match cs_algorithm {
-        CoinSelectionAlgo::BranchAndBound => {
-            coin_select_bnb(Duration::from_secs(10), coin_selector.clone())
-                .map_or_else(|| coin_selector.select_until_finished(), |cs| cs.finish())?
-        }
-        _ => coin_selector.select_until_finished()?,
-    };
-    let (_, selection_meta) = selection.best_strategy();
-
-    // get the selected utxos
-    let selected_txos = selection.apply_selection(&candidates).collect::<Vec<_>>();
-
-    if let Some(drain_value) = selection_meta.drain_value {
-        change_output.value = drain_value;
-        // if the selection tells us to use change and the change value is sufficient, we add it as an output
-        outputs.push(change_output)
-    }
-
-    let mut transaction = Transaction {
-        version: 0x02,
-        // because the temporary planning module does not support timelocks, we can use the chain
-        // tip as the `lock_time` for anti-fee-sniping purposes
-        lock_time: chain
-            .get_chain_tip()?
-            .and_then(|block_id| LockTime::from_height(block_id.height).ok())
-            .unwrap_or(LockTime::ZERO)
-            .into(),
-        input: selected_txos
-            .iter()
-            .map(|(_, utxo)| TxIn {
-                previous_output: utxo.outpoint,
-                sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
-                ..Default::default()
-            })
-            .collect(),
-        output: outputs,
-    };
-
-    let prevouts = selected_txos
-        .iter()
-        .map(|(_, utxo)| utxo.txout.clone())
-        .collect::<Vec<_>>();
-    let sighash_prevouts = Prevouts::All(&prevouts);
-
-    // first, set tx values for the plan so that we don't change them while signing
-    for (i, (plan, _)) in selected_txos.iter().enumerate() {
-        if let Some(sequence) = plan.required_sequence() {
-            transaction.input[i].sequence = sequence
-        }
-    }
-
-    // create a short lived transaction
-    let _sighash_tx = transaction.clone();
-    let mut sighash_cache = SighashCache::new(&_sighash_tx);
-
-    for (i, (plan, _)) in selected_txos.iter().enumerate() {
-        let requirements = plan.requirements();
-        let mut auth_data = bdk_tmp_plan::SatisfactionMaterial::default();
-        assert!(
-            !requirements.requires_hash_preimages(),
-            "can't have hash pre-images since we didn't provide any."
-        );
-        assert!(
-            requirements.signatures.sign_with_keymap(
-                i,
-                keymap,
-                &sighash_prevouts,
-                None,
-                None,
-                &mut sighash_cache,
-                &mut auth_data,
-                &Secp256k1::default(),
-            )?,
-            "we should have signed with this input."
-        );
-
-        match plan.try_complete(&auth_data) {
-            bdk_tmp_plan::PlanState::Complete {
-                final_script_sig,
-                final_script_witness,
-            } => {
-                if let Some(witness) = final_script_witness {
-                    transaction.input[i].witness = witness;
-                }
-
-                if let Some(script_sig) = final_script_sig {
-                    transaction.input[i].script_sig = script_sig;
-                }
-            }
-            bdk_tmp_plan::PlanState::Incomplete(_) => {
-                return Err(anyhow::anyhow!(
-                    "we weren't able to complete the plan with our keys."
-                ));
-            }
-        }
-    }
-
-    let change_info = if selection_meta.drain_value.is_some() {
-        Some((additions, (internal_keychain, change_index)))
-    } else {
-        None
-    };
-
-    Ok((transaction, change_info))
-}
-
-#[allow(clippy::type_complexity)]
-pub fn planned_utxos<A: Anchor, O: ChainOracle, K: Clone + bdk_tmp_plan::CanDerive>(
-    graph: &KeychainTxGraph<A>,
-    chain: &O,
-    assets: &bdk_tmp_plan::Assets<K>,
-) -> Result<Vec<(bdk_tmp_plan::Plan<K>, FullTxOut<A>)>, O::Error> {
-    let chain_tip = chain.get_chain_tip()?.unwrap_or_default();
-    let outpoints = graph.index.outpoints().iter().cloned();
-    graph
-        .graph()
-        .try_filter_chain_unspents(chain, chain_tip, outpoints)
-        .filter_map(
-            #[allow(clippy::type_complexity)]
-            |r| -> Option<Result<(bdk_tmp_plan::Plan<K>, FullTxOut<A>), _>> {
-                let (k, i, full_txo) = match r {
-                    Err(err) => return Some(Err(err)),
-                    Ok(((k, i), full_txo)) => (k, i, full_txo),
-                };
-                let desc = graph
-                    .index
-                    .keychains()
-                    .get(&k)
-                    .expect("keychain must exist")
-                    .at_derivation_index(i);
-                let plan = bdk_tmp_plan::plan_satisfaction(&desc, assets)?;
-                Some(Ok((plan, full_txo)))
-            },
-        )
-        .collect()
-}
-
-pub fn handle_commands<S: clap::Subcommand, A: Anchor, O: ChainOracle, C>(
-    graph: &Mutex<KeychainTxGraph<A>>,
-    db: &Mutex<Database<C>>,
-    chain: &Mutex<O>,
-    keymap: &HashMap<DescriptorPublicKey, DescriptorSecretKey>,
-    network: Network,
-    broadcast: impl FnOnce(&Transaction) -> anyhow::Result<()>,
-    cmd: Commands<S>,
-) -> anyhow::Result<()>
-where
-    O::Error: std::error::Error + Send + Sync + 'static,
-    C: Default + Append + DeserializeOwned + Serialize + From<KeychainAdditions<A>>,
-{
-    match cmd {
-        Commands::ChainSpecific(_) => unreachable!("example code should handle this!"),
-        Commands::Address { addr_cmd } => {
-            let graph = &mut *graph.lock().unwrap();
-            run_address_cmd(graph, db, network, addr_cmd)
-        }
-        Commands::Balance => {
-            let graph = &*graph.lock().unwrap();
-            let chain = &*chain.lock().unwrap();
-            run_balance_cmd(graph, chain).map_err(anyhow::Error::from)
-        }
-        Commands::TxOut { txout_cmd } => {
-            let graph = &*graph.lock().unwrap();
-            let chain = &*chain.lock().unwrap();
-            run_txo_cmd(graph, chain, network, txout_cmd)
-        }
-        Commands::Send {
-            value,
-            address,
-            coin_select,
-        } => {
-            let chain = &*chain.lock().unwrap();
-            run_send_cmd(
-                graph,
-                db,
-                chain,
-                keymap,
-                coin_select,
-                address,
-                value,
-                broadcast,
-            )
-        }
-    }
-}
-
-#[allow(clippy::type_complexity)]
-pub fn init<'m, S: clap::Subcommand, C>(
-    db_magic: &'m [u8],
-    db_default_path: &str,
-) -> anyhow::Result<(
-    Args<S>,
-    KeyMap,
-    KeychainTxOutIndex<Keychain>,
-    Mutex<Database<'m, C>>,
-    C,
-)>
-where
-    C: Default + Append + Serialize + DeserializeOwned,
-{
-    if std::env::var("BDK_DB_PATH").is_err() {
-        std::env::set_var("BDK_DB_PATH", db_default_path);
-    }
-    let args = Args::<S>::parse();
-    let secp = Secp256k1::default();
-
-    let mut index = KeychainTxOutIndex::<Keychain>::default();
-
-    let (descriptor, mut keymap) =
-        Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, &args.descriptor)?;
-    index.add_keychain(Keychain::External, descriptor);
-
-    if let Some((internal_descriptor, internal_keymap)) = args
-        .change_descriptor
-        .as_ref()
-        .map(|desc_str| Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, desc_str))
-        .transpose()?
-    {
-        keymap.extend(internal_keymap);
-        index.add_keychain(Keychain::Internal, internal_descriptor);
-    }
-
-    let mut db_backend = match Store::<'m, C>::new_from_path(db_magic, &args.db_path) {
-        Ok(db_backend) => db_backend,
-        // we cannot return `err` directly as it has lifetime `'m`
-        Err(err) => return Err(anyhow::anyhow!("failed to init db backend: {:?}", err)),
-    };
-
-    let init_changeset = db_backend.load_from_persistence()?;
-
-    Ok((
-        args,
-        keymap,
-        index,
-        Mutex::new(Database::new(db_backend)),
-        init_changeset,
-    ))
-}
--- a/example-crates/example_electrum/Cargo.toml
+++ b/example-crates/example_electrum/Cargo.toml
@@ -1,11 +0,0 @@
-[package]
-name = "example_electrum"
-version = "0.2.0"
-edition = "2021"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
-bdk_chain = { path = "../../crates/chain", features = ["serde"] }
-bdk_electrum = { path = "../../crates/electrum" }
-example_cli = { path = "../example_cli" }
--- a/example-crates/keychain_tracker_electrum/.gitignore
+++ b/example-crates/keychain_tracker_electrum/.gitignore
@@ -0,0 +1 @@
+/target
--- a/example-crates/keychain_tracker_electrum/Cargo.toml
+++ b/example-crates/keychain_tracker_electrum/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "keychain_tracker_electrum_example"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+bdk_chain = { path = "../../crates/chain", features = ["serde"] }
+bdk_electrum = { path = "../../crates/electrum" }
+keychain_tracker_example_cli = { path = "../keychain_tracker_example_cli"}
--- a/example-crates/keychain_tracker_electrum/README.md
+++ b/example-crates/keychain_tracker_electrum/README.md
@@ -0,0 +1,6 @@
+# Keychain Tracker with electrum
+
+This example shows how you use the `KeychainTracker` from `bdk_chain` to create a simple command
+line wallet.
+
+
--- a/example-crates/keychain_tracker_electrum/src/main.rs
+++ b/example-crates/keychain_tracker_electrum/src/main.rs
@@ -1,33 +1,19 @@
-use std::{
-    collections::BTreeMap,
-    io::{self, Write},
-    sync::Mutex,
-};
-
-use bdk_chain::{
-    bitcoin::{Address, BlockHash, Network, OutPoint, Txid},
-    indexed_tx_graph::{IndexedAdditions, IndexedTxGraph},
-    keychain::LocalChangeSet,
-    local_chain::LocalChain,
-    Append, ConfirmationHeightAnchor,
-};
+use bdk_chain::bitcoin::{Address, OutPoint, Txid};
+use bdk_electrum::bdk_chain::{self, bitcoin::Network, TxHeight};
 use bdk_electrum::{
    electrum_client::{self, ElectrumApi},
    ElectrumExt, ElectrumUpdate,
 };
-use example_cli::{
+use keychain_tracker_example_cli::{
+    self as cli,
    anyhow::{self, Context},
    clap::{self, Parser, Subcommand},
-    Keychain,
 };
-
-const DB_MAGIC: &[u8] = b"bdk_example_electrum";
-const DB_PATH: &str = ".bdk_electrum_example.db";
-const ASSUME_FINAL_DEPTH: usize = 10;
+use std::{collections::BTreeMap, fmt::Debug, io, io::Write};

 #[derive(Subcommand, Debug, Clone)]
 enum ElectrumCommands {
-    /// Scans the addresses in the wallet using the electrum API.
+    /// Scans the addresses in the wallet using the esplora API.
    Scan {
        /// When a gap this large has been found for a keychain, it will stop.
        #[clap(long, default_value = "5")]
@@ -35,7 +21,7 @@ enum ElectrumCommands {
        #[clap(flatten)]
        scan_options: ScanOptions,
    },
-    /// Scans particular addresses using the electrum API.
+    /// Scans particular addresses using the esplora API.
    Sync {
        /// Scan all the unused addresses.
        #[clap(long)]
@@ -61,23 +47,8 @@ pub struct ScanOptions {
    pub batch_size: usize,
 }

-type ChangeSet = LocalChangeSet<Keychain, ConfirmationHeightAnchor>;
-
 fn main() -> anyhow::Result<()> {
-    let (args, keymap, index, db, init_changeset) =
-        example_cli::init::<ElectrumCommands, ChangeSet>(DB_MAGIC, DB_PATH)?;
-
-    let graph = Mutex::new({
-        let mut graph = IndexedTxGraph::new(index);
-        graph.apply_additions(init_changeset.indexed_additions);
-        graph
-    });
-
-    let chain = Mutex::new({
-        let mut chain = LocalChain::default();
-        chain.apply_changeset(init_changeset.chain_changeset);
-        chain
-    });
+    let (args, keymap, tracker, db) = cli::init::<ElectrumCommands, _>()?;

    let electrum_url = match args.network {
        Network::Bitcoin => "ssl://electrum.blockstream.info:50002",
@@ -91,40 +62,34 @@ fn main() -> anyhow::Result<()> {

    let client = electrum_client::Client::from_config(electrum_url, config)?;

-    let electrum_cmd = match &args.command {
-        example_cli::Commands::ChainSpecific(electrum_cmd) => electrum_cmd,
-        general_cmd => {
-            let res = example_cli::handle_commands(
-                &graph,
-                &db,
-                &chain,
-                &keymap,
-                args.network,
-                |tx| {
-                    client
-                        .transaction_broadcast(tx)
-                        .map(|_| ())
-                        .map_err(anyhow::Error::from)
+    let electrum_cmd = match args.command.clone() {
+        cli::Commands::ChainSpecific(electrum_cmd) => electrum_cmd,
+        general_command => {
+            return cli::handle_commands(
+                general_command,
+                |transaction| {
+                    let _txid = client.transaction_broadcast(transaction)?;
+                    Ok(())
                },
-                general_cmd.clone(),
-            );
-
-            db.lock().unwrap().commit()?;
-            return res;
+                &tracker,
+                &db,
+                args.network,
+                &keymap,
+            )
        }
    };

-    let response = match electrum_cmd.clone() {
+    let response = match electrum_cmd {
        ElectrumCommands::Scan {
            stop_gap,
-            scan_options,
+            scan_options: scan_option,
        } => {
-            let (keychain_spks, local_chain) = {
-                let graph = &*graph.lock().unwrap();
-                let chain = &*chain.lock().unwrap();
-
-                let keychain_spks = graph
-                    .index
+            let (spk_iterators, local_chain) = {
+                // Get a short lock on the tracker to get the spks iterators
+                // and local chain state
+                let tracker = &*tracker.lock().unwrap();
+                let spk_iterators = tracker
+                    .txout_index
                    .spks_of_all_keychains()
                    .into_iter()
                    .map(|(keychain, iter)| {
@@ -141,40 +106,29 @@ fn main() -> anyhow::Result<()> {
                        (keychain, spk_iter)
                    })
                    .collect::<BTreeMap<_, _>>();
-
-                let c = chain
-                    .blocks()
-                    .iter()
-                    .rev()
-                    .take(ASSUME_FINAL_DEPTH)
-                    .map(|(k, v)| (*k, *v))
-                    .collect::<BTreeMap<u32, BlockHash>>();
-
-                (keychain_spks, c)
+                let local_chain = tracker.chain().checkpoints().clone();
+                (spk_iterators, local_chain)
            };

-            client
-                .scan(
-                    &local_chain,
-                    keychain_spks,
-                    core::iter::empty(),
-                    core::iter::empty(),
-                    stop_gap,
-                    scan_options.batch_size,
-                )
-                .context("scanning the blockchain")?
+            // we scan the spks **without** a lock on the tracker
+            client.scan(
+                &local_chain,
+                spk_iterators,
+                core::iter::empty(),
+                core::iter::empty(),
+                stop_gap,
+                scan_option.batch_size,
+            )?
        }
        ElectrumCommands::Sync {
            mut unused_spks,
-            all_spks,
            mut utxos,
            mut unconfirmed,
+            all_spks,
            scan_options,
        } => {
            // Get a short lock on the tracker to get the spks we're interested in
-            let graph = graph.lock().unwrap();
-            let chain = chain.lock().unwrap();
-            let chain_tip = chain.tip().unwrap_or_default();
+            let tracker = tracker.lock().unwrap();

            if !(all_spks || unused_spks || utxos || unconfirmed) {
                unused_spks = true;
@@ -187,8 +141,8 @@ fn main() -> anyhow::Result<()> {
            let mut spks: Box<dyn Iterator<Item = bdk_chain::bitcoin::Script>> =
                Box::new(core::iter::empty());
            if all_spks {
-                let all_spks = graph
-                    .index
+                let all_spks = tracker
+                    .txout_index
                    .all_spks()
                    .iter()
                    .map(|(k, v)| (*k, v.clone()))
@@ -199,8 +153,8 @@ fn main() -> anyhow::Result<()> {
                })));
            }
            if unused_spks {
-                let unused_spks = graph
-                    .index
+                let unused_spks = tracker
+                    .txout_index
                    .unused_spks(..)
                    .map(|(k, v)| (*k, v.clone()))
                    .collect::<Vec<_>>();
@@ -218,14 +172,10 @@ fn main() -> anyhow::Result<()> {
            let mut outpoints: Box<dyn Iterator<Item = OutPoint>> = Box::new(core::iter::empty());

            if utxos {
-                let init_outpoints = graph.index.outpoints().iter().cloned();
-
-                let utxos = graph
-                    .graph()
-                    .filter_chain_unspents(&*chain, chain_tip, init_outpoints)
+                let utxos = tracker
+                    .full_utxos()
                    .map(|(_, utxo)| utxo)
                    .collect::<Vec<_>>();
-
                outpoints = Box::new(
                    utxos
                        .into_iter()
@@ -242,77 +192,54 @@ fn main() -> anyhow::Result<()> {
            let mut txids: Box<dyn Iterator<Item = Txid>> = Box::new(core::iter::empty());

            if unconfirmed {
-                let unconfirmed_txids = graph
-                    .graph()
-                    .list_chain_txs(&*chain, chain_tip)
-                    .filter(|canonical_tx| !canonical_tx.observed_as.is_confirmed())
-                    .map(|canonical_tx| canonical_tx.node.txid)
-                    .collect::<Vec<Txid>>();
+                let unconfirmed_txids = tracker
+                    .chain()
+                    .range_txids_by_height(TxHeight::Unconfirmed..)
+                    .map(|(_, txid)| *txid)
+                    .collect::<Vec<_>>();

                txids = Box::new(unconfirmed_txids.into_iter().inspect(|txid| {
                    eprintln!("Checking if {} is confirmed yet", txid);
                }));
            }

-            let c = chain
-                .blocks()
-                .iter()
-                .rev()
-                .take(ASSUME_FINAL_DEPTH)
-                .map(|(k, v)| (*k, *v))
-                .collect::<BTreeMap<u32, BlockHash>>();
+            let local_chain = tracker.chain().checkpoints().clone();
+            // drop lock on tracker
+            drop(tracker);

-            // drop lock on graph and chain
-            drop((graph, chain));
-
-            let update = client
-                .scan_without_keychain(&c, spks, txids, outpoints, scan_options.batch_size)
-                .context("scanning the blockchain")?;
+            // we scan the spks **without** a lock on the tracker
            ElectrumUpdate {
-                graph_update: update.graph_update,
-                chain_update: update.chain_update,
-                keychain_update: BTreeMap::new(),
+                chain_update: client
+                    .scan_without_keychain(
+                        &local_chain,
+                        spks,
+                        txids,
+                        outpoints,
+                        scan_options.batch_size,
+                    )
+                    .context("scanning the blockchain")?,
+                ..Default::default()
            }
        }
    };

-    let missing_txids = {
-        let graph = &*graph.lock().unwrap();
-        response.missing_full_txs(graph.graph())
-    };
+    let missing_txids = response.missing_full_txs(&*tracker.lock().unwrap());

-    let now = std::time::UNIX_EPOCH
-        .elapsed()
-        .expect("must get time")
-        .as_secs();
+    // fetch the missing full transactions **without** a lock on the tracker
+    let new_txs = client
+        .batch_transaction_get(missing_txids)
+        .context("fetching full transactions")?;

-    let final_update = response.finalize(&client, Some(now), missing_txids)?;
-
-    let db_changeset = {
-        let mut chain = chain.lock().unwrap();
-        let mut graph = graph.lock().unwrap();
-
-        let chain_changeset = chain.apply_update(final_update.chain)?;
-
-        let indexed_additions = {
-            let mut additions = IndexedAdditions::<ConfirmationHeightAnchor, _>::default();
-            let (_, index_additions) = graph.index.reveal_to_target_multi(&final_update.keychain);
-            additions.append(IndexedAdditions {
-                index_additions,
-                ..Default::default()
-            });
-            additions.append(graph.apply_update(final_update.graph));
-            additions
+    {
+        // Get a final short lock to apply the changes
+        let mut tracker = tracker.lock().unwrap();
+        let changeset = {
+            let scan = response.into_keychain_scan(new_txs, &*tracker)?;
+            tracker.determine_changeset(&scan)?
        };
-
-        ChangeSet {
-            indexed_additions,
-            chain_changeset,
-        }
+        db.lock().unwrap().append_changeset(&changeset)?;
+        tracker.apply_changeset(changeset);
    };

-    let mut db = db.lock().unwrap();
-    db.stage(db_changeset);
-    db.commit()?;
    Ok(())
 }
--- a/example-crates/keychain_tracker_esplora/.gitignore
+++ b/example-crates/keychain_tracker_esplora/.gitignore
@@ -0,0 +1,3 @@
+/target
+Cargo.lock
+.bdk_example_db
--- a/example-crates/keychain_tracker_esplora/Cargo.toml
+++ b/example-crates/keychain_tracker_esplora/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "keychain_tracker_esplora_example"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bdk_chain = { path = "../../crates/chain", features = ["serde", "miniscript"] }
+bdk_esplora = { path = "../../crates/esplora" }
+keychain_tracker_example_cli = { path = "../keychain_tracker_example_cli" }
--- a/example-crates/keychain_tracker_esplora/src/main.rs
+++ b/example-crates/keychain_tracker_esplora/src/main.rs
@@ -0,0 +1,241 @@
+use bdk_chain::bitcoin::{Address, OutPoint, Txid};
+use bdk_chain::{bitcoin::Network, TxHeight};
+use bdk_esplora::esplora_client;
+use bdk_esplora::EsploraExt;
+
+use std::io::{self, Write};
+
+use keychain_tracker_example_cli::{
+    self as cli,
+    anyhow::{self, Context},
+    clap::{self, Parser, Subcommand},
+};
+
+#[derive(Subcommand, Debug, Clone)]
+enum EsploraCommands {
+    /// Scans the addresses in the wallet using the esplora API.
+    Scan {
+        /// When a gap this large has been found for a keychain, it will stop.
+        #[clap(long, default_value = "5")]
+        stop_gap: usize,
+
+        #[clap(flatten)]
+        scan_options: ScanOptions,
+    },
+    /// Scans particular addresses using esplora API.
+    Sync {
+        /// Scan all the unused addresses.
+        #[clap(long)]
+        unused_spks: bool,
+        /// Scan every address that you have derived.
+        #[clap(long)]
+        all_spks: bool,
+        /// Scan unspent outpoints for spends or changes to confirmation status of residing tx.
+        #[clap(long)]
+        utxos: bool,
+        /// Scan unconfirmed transactions for updates.
+        #[clap(long)]
+        unconfirmed: bool,
+
+        #[clap(flatten)]
+        scan_options: ScanOptions,
+    },
+}
+
+#[derive(Parser, Debug, Clone, PartialEq)]
+pub struct ScanOptions {
+    #[clap(long, default_value = "5")]
+    pub parallel_requests: usize,
+}
+
+fn main() -> anyhow::Result<()> {
+    let (args, keymap, keychain_tracker, db) = cli::init::<EsploraCommands, _>()?;
+    let esplora_url = match args.network {
+        Network::Bitcoin => "https://mempool.space/api",
+        Network::Testnet => "https://mempool.space/testnet/api",
+        Network::Regtest => "http://localhost:3002",
+        Network::Signet => "https://mempool.space/signet/api",
+    };
+
+    let client = esplora_client::Builder::new(esplora_url).build_blocking()?;
+
+    let esplora_cmd = match args.command {
+        cli::Commands::ChainSpecific(esplora_cmd) => esplora_cmd,
+        general_command => {
+            return cli::handle_commands(
+                general_command,
+                |transaction| Ok(client.broadcast(transaction)?),
+                &keychain_tracker,
+                &db,
+                args.network,
+                &keymap,
+            )
+        }
+    };
+
+    match esplora_cmd {
+        EsploraCommands::Scan {
+            stop_gap,
+            scan_options,
+        } => {
+            let (spk_iterators, local_chain) = {
+                // Get a short lock on the tracker to get the spks iterators
+                // and local chain state
+                let tracker = &*keychain_tracker.lock().unwrap();
+                let spk_iterators = tracker
+                    .txout_index
+                    .spks_of_all_keychains()
+                    .into_iter()
+                    .map(|(keychain, iter)| {
+                        let mut first = true;
+                        (
+                            keychain,
+                            iter.inspect(move |(i, _)| {
+                                if first {
+                                    eprint!("\nscanning {}: ", keychain);
+                                    first = false;
+                                }
+
+                                eprint!("{} ", i);
+                                let _ = io::stdout().flush();
+                            }),
+                        )
+                    })
+                    .collect();
+
+                let local_chain = tracker.chain().checkpoints().clone();
+                (spk_iterators, local_chain)
+            };
+
+            // we scan the iterators **without** a lock on the tracker
+            let wallet_scan = client
+                .scan(
+                    &local_chain,
+                    spk_iterators,
+                    core::iter::empty(),
+                    core::iter::empty(),
+                    stop_gap,
+                    scan_options.parallel_requests,
+                )
+                .context("scanning the blockchain")?;
+            eprintln!();
+
+            {
+                // we take a short lock to apply results to tracker and db
+                let tracker = &mut *keychain_tracker.lock().unwrap();
+                let db = &mut *db.lock().unwrap();
+                let changeset = tracker.apply_update(wallet_scan)?;
+                db.append_changeset(&changeset)?;
+            }
+        }
+        EsploraCommands::Sync {
+            mut unused_spks,
+            mut utxos,
+            mut unconfirmed,
+            all_spks,
+            scan_options,
+        } => {
+            // Get a short lock on the tracker to get the spks we're interested in
+            let tracker = keychain_tracker.lock().unwrap();
+
+            if !(all_spks || unused_spks || utxos || unconfirmed) {
+                unused_spks = true;
+                unconfirmed = true;
+                utxos = true;
+            } else if all_spks {
+                unused_spks = false;
+            }
+
+            let mut spks: Box<dyn Iterator<Item = bdk_chain::bitcoin::Script>> =
+                Box::new(core::iter::empty());
+            if all_spks {
+                let all_spks = tracker
+                    .txout_index
+                    .all_spks()
+                    .iter()
+                    .map(|(k, v)| (*k, v.clone()))
+                    .collect::<Vec<_>>();
+                spks = Box::new(spks.chain(all_spks.into_iter().map(|(index, script)| {
+                    eprintln!("scanning {:?}", index);
+                    script
+                })));
+            }
+            if unused_spks {
+                let unused_spks = tracker
+                    .txout_index
+                    .unused_spks(..)
+                    .map(|(k, v)| (*k, v.clone()))
+                    .collect::<Vec<_>>();
+                spks = Box::new(spks.chain(unused_spks.into_iter().map(|(index, script)| {
+                    eprintln!(
+                        "Checking if address {} {:?} has been used",
+                        Address::from_script(&script, args.network).unwrap(),
+                        index
+                    );
+
+                    script
+                })));
+            }
+
+            let mut outpoints: Box<dyn Iterator<Item = OutPoint>> = Box::new(core::iter::empty());
+
+            if utxos {
+                let utxos = tracker
+                    .full_utxos()
+                    .map(|(_, utxo)| utxo)
+                    .collect::<Vec<_>>();
+                outpoints = Box::new(
+                    utxos
+                        .into_iter()
+                        .inspect(|utxo| {
+                            eprintln!(
+                                "Checking if outpoint {} (value: {}) has been spent",
+                                utxo.outpoint, utxo.txout.value
+                            );
+                        })
+                        .map(|utxo| utxo.outpoint),
+                );
+            };
+
+            let mut txids: Box<dyn Iterator<Item = Txid>> = Box::new(core::iter::empty());
+
+            if unconfirmed {
+                let unconfirmed_txids = tracker
+                    .chain()
+                    .range_txids_by_height(TxHeight::Unconfirmed..)
+                    .map(|(_, txid)| *txid)
+                    .collect::<Vec<_>>();
+
+                txids = Box::new(unconfirmed_txids.into_iter().inspect(|txid| {
+                    eprintln!("Checking if {} is confirmed yet", txid);
+                }));
+            }
+
+            let local_chain = tracker.chain().checkpoints().clone();
+
+            // drop lock on tracker
+            drop(tracker);
+
+            // we scan the desired spks **without** a lock on the tracker
+            let scan = client
+                .scan_without_keychain(
+                    &local_chain,
+                    spks,
+                    txids,
+                    outpoints,
+                    scan_options.parallel_requests,
+                )
+                .context("scanning the blockchain")?;
+
+            {
+                // we take a short lock to apply the results to the tracker and db
+                let tracker = &mut *keychain_tracker.lock().unwrap();
+                let changeset = tracker.apply_update(scan.into())?;
+                let db = &mut *db.lock().unwrap();
+                db.append_changeset(&changeset)?;
+            }
+        }
+    }
+
+    Ok(())
+}
--- a/example-crates/keychain_tracker_example_cli/.gitignore
+++ b/example-crates/keychain_tracker_example_cli/.gitignore
@@ -0,0 +1 @@
+/target
--- a/example-crates/keychain_tracker_example_cli/Cargo.toml
+++ b/example-crates/keychain_tracker_example_cli/Cargo.toml
@@ -1,10 +1,9 @@
 [package]
-name = "example_cli"
-version = "0.2.0"
+name = "keychain_tracker_example_cli"
+version = "0.1.0"
 edition = "2021"

 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
 [dependencies]
 bdk_chain = { path = "../../crates/chain", features = ["serde", "miniscript"]}
 bdk_file_store = { path = "../../crates/file_store" }
--- a/example-crates/keychain_tracker_example_cli/README.md
+++ b/example-crates/keychain_tracker_example_cli/README.md
@@ -0,0 +1 @@
+Provides common command line processing logic between examples using the `KeychainTracker`
--- a/example-crates/keychain_tracker_example_cli/src/lib.rs
+++ b/example-crates/keychain_tracker_example_cli/src/lib.rs
@@ -0,0 +1,692 @@
+pub extern crate anyhow;
+use anyhow::{anyhow, Context, Result};
+use bdk_chain::{
+    bitcoin::{
+        secp256k1::Secp256k1,
+        util::sighash::{Prevouts, SighashCache},
+        Address, LockTime, Network, Sequence, Transaction, TxIn, TxOut,
+    },
+    chain_graph::InsertTxError,
+    keychain::{DerivationAdditions, KeychainChangeSet, KeychainTracker},
+    miniscript::{
+        descriptor::{DescriptorSecretKey, KeyMap},
+        Descriptor, DescriptorPublicKey,
+    },
+    sparse_chain::{self, ChainPosition},
+    DescriptorExt, FullTxOut,
+};
+use bdk_coin_select::{coin_select_bnb, CoinSelector, CoinSelectorOpt, WeightedValue};
+use bdk_file_store::KeychainStore;
+use clap::{Parser, Subcommand};
+use std::{
+    cmp::Reverse, collections::HashMap, fmt::Debug, path::PathBuf, sync::Mutex, time::Duration,
+};
+
+pub use bdk_file_store;
+pub use clap;
+
+#[derive(Parser)]
+#[clap(author, version, about, long_about = None)]
+#[clap(propagate_version = true)]
+pub struct Args<C: clap::Subcommand> {
+    #[clap(env = "DESCRIPTOR")]
+    pub descriptor: String,
+    #[clap(env = "CHANGE_DESCRIPTOR")]
+    pub change_descriptor: Option<String>,
+
+    #[clap(env = "BITCOIN_NETWORK", long, default_value = "signet")]
+    pub network: Network,
+
+    #[clap(env = "BDK_DB_PATH", long, default_value = ".bdk_example_db")]
+    pub db_path: PathBuf,
+
+    #[clap(env = "BDK_CP_LIMIT", long, default_value = "20")]
+    pub cp_limit: usize,
+
+    #[clap(subcommand)]
+    pub command: Commands<C>,
+}
+
+#[derive(Subcommand, Debug, Clone)]
+pub enum Commands<C: clap::Subcommand> {
+    #[clap(flatten)]
+    ChainSpecific(C),
+    /// Address generation and inspection.
+    Address {
+        #[clap(subcommand)]
+        addr_cmd: AddressCmd,
+    },
+    /// Get the wallet balance.
+    Balance,
+    /// TxOut related commands.
+    #[clap(name = "txout")]
+    TxOut {
+        #[clap(subcommand)]
+        txout_cmd: TxOutCmd,
+    },
+    /// Send coins to an address.
+    Send {
+        value: u64,
+        address: Address,
+        #[clap(short, default_value = "largest-first")]
+        coin_select: CoinSelectionAlgo,
+    },
+}
+
+#[derive(Clone, Debug)]
+pub enum CoinSelectionAlgo {
+    LargestFirst,
+    SmallestFirst,
+    OldestFirst,
+    NewestFirst,
+    BranchAndBound,
+}
+
+impl Default for CoinSelectionAlgo {
+    fn default() -> Self {
+        Self::LargestFirst
+    }
+}
+
+impl core::str::FromStr for CoinSelectionAlgo {
+    type Err = anyhow::Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        use CoinSelectionAlgo::*;
+        Ok(match s {
+            "largest-first" => LargestFirst,
+            "smallest-first" => SmallestFirst,
+            "oldest-first" => OldestFirst,
+            "newest-first" => NewestFirst,
+            "bnb" => BranchAndBound,
+            unknown => return Err(anyhow!("unknown coin selection algorithm '{}'", unknown)),
+        })
+    }
+}
+
+impl core::fmt::Display for CoinSelectionAlgo {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        use CoinSelectionAlgo::*;
+        write!(
+            f,
+            "{}",
+            match self {
+                LargestFirst => "largest-first",
+                SmallestFirst => "smallest-first",
+                OldestFirst => "oldest-first",
+                NewestFirst => "newest-first",
+                BranchAndBound => "bnb",
+            }
+        )
+    }
+}
+
+#[derive(Subcommand, Debug, Clone)]
+pub enum AddressCmd {
+    /// Get the next unused address.
+    Next,
+    /// Get a new address regardless of the existing unused addresses.
+    New,
+    /// List all addresses
+    List {
+        #[clap(long)]
+        change: bool,
+    },
+    Index,
+}
+
+#[derive(Subcommand, Debug, Clone)]
+pub enum TxOutCmd {
+    List {
+        /// Return only spent outputs.
+        #[clap(short, long)]
+        spent: bool,
+        /// Return only unspent outputs.
+        #[clap(short, long)]
+        unspent: bool,
+        /// Return only confirmed outputs.
+        #[clap(long)]
+        confirmed: bool,
+        /// Return only unconfirmed outputs.
+        #[clap(long)]
+        unconfirmed: bool,
+    },
+}
+
+#[derive(
+    Debug, Clone, Copy, PartialOrd, Ord, PartialEq, Eq, serde::Deserialize, serde::Serialize,
+)]
+pub enum Keychain {
+    External,
+    Internal,
+}
+
+impl core::fmt::Display for Keychain {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Keychain::External => write!(f, "external"),
+            Keychain::Internal => write!(f, "internal"),
+        }
+    }
+}
+
+/// A structure defining the output of an [`AddressCmd`]` execution.
+#[derive(serde::Serialize, serde::Deserialize)]
+pub struct AddrsOutput {
+    keychain: String,
+    index: u32,
+    addrs: Address,
+    used: bool,
+}
+
+pub fn run_address_cmd<P>(
+    tracker: &Mutex<KeychainTracker<Keychain, P>>,
+    db: &Mutex<KeychainStore<Keychain, P>>,
+    addr_cmd: AddressCmd,
+    network: Network,
+) -> Result<()>
+where
+    P: bdk_chain::sparse_chain::ChainPosition,
+    KeychainChangeSet<Keychain, P>: serde::Serialize + serde::de::DeserializeOwned,
+{
+    let mut tracker = tracker.lock().unwrap();
+    let txout_index = &mut tracker.txout_index;
+
+    let addr_cmmd_output = match addr_cmd {
+        AddressCmd::Next => Some(txout_index.next_unused_spk(&Keychain::External)),
+        AddressCmd::New => Some(txout_index.reveal_next_spk(&Keychain::External)),
+        _ => None,
+    };
+
+    if let Some(((index, spk), additions)) = addr_cmmd_output {
+        let mut db = db.lock().unwrap();
+        // update database since we're about to give out a new address
+        db.append_changeset(&additions.into())?;
+
+        let spk = spk.clone();
+        let address =
+            Address::from_script(&spk, network).expect("should always be able to derive address");
+        eprintln!("This is the address at index {}", index);
+        println!("{}", address);
+    }
+
+    match addr_cmd {
+        AddressCmd::Next | AddressCmd::New => {
+            /* covered */
+            Ok(())
+        }
+        AddressCmd::Index => {
+            for (keychain, derivation_index) in txout_index.last_revealed_indices() {
+                println!("{:?}: {}", keychain, derivation_index);
+            }
+            Ok(())
+        }
+        AddressCmd::List { change } => {
+            let target_keychain = match change {
+                true => Keychain::Internal,
+                false => Keychain::External,
+            };
+            for (index, spk) in txout_index.revealed_spks_of_keychain(&target_keychain) {
+                let address = Address::from_script(spk, network)
+                    .expect("should always be able to derive address");
+                println!(
+                    "{:?} {} used:{}",
+                    index,
+                    address,
+                    txout_index.is_used(&(target_keychain, index))
+                );
+            }
+            Ok(())
+        }
+    }
+}
+
+pub fn run_balance_cmd<P: ChainPosition>(tracker: &Mutex<KeychainTracker<Keychain, P>>) {
+    let tracker = tracker.lock().unwrap();
+    let (confirmed, unconfirmed) =
+        tracker
+            .full_utxos()
+            .fold((0, 0), |(confirmed, unconfirmed), (_, utxo)| {
+                if utxo.chain_position.height().is_confirmed() {
+                    (confirmed + utxo.txout.value, unconfirmed)
+                } else {
+                    (confirmed, unconfirmed + utxo.txout.value)
+                }
+            });
+
+    println!("confirmed: {}", confirmed);
+    println!("unconfirmed: {}", unconfirmed);
+}
+
+pub fn run_txo_cmd<K: Debug + Clone + Ord, P: ChainPosition>(
+    txout_cmd: TxOutCmd,
+    tracker: &Mutex<KeychainTracker<K, P>>,
+    network: Network,
+) {
+    match txout_cmd {
+        TxOutCmd::List {
+            unspent,
+            spent,
+            confirmed,
+            unconfirmed,
+        } => {
+            let tracker = tracker.lock().unwrap();
+            #[allow(clippy::type_complexity)] // FIXME
+            let txouts: Box<dyn Iterator<Item = (&(K, u32), FullTxOut<P>)>> = match (unspent, spent)
+            {
+                (true, false) => Box::new(tracker.full_utxos()),
+                (false, true) => Box::new(
+                    tracker
+                        .full_txouts()
+                        .filter(|(_, txout)| txout.spent_by.is_some()),
+                ),
+                _ => Box::new(tracker.full_txouts()),
+            };
+
+            #[allow(clippy::type_complexity)] // FIXME
+            let txouts: Box<dyn Iterator<Item = (&(K, u32), FullTxOut<P>)>> =
+                match (confirmed, unconfirmed) {
+                    (true, false) => Box::new(
+                        txouts.filter(|(_, txout)| txout.chain_position.height().is_confirmed()),
+                    ),
+                    (false, true) => Box::new(
+                        txouts.filter(|(_, txout)| !txout.chain_position.height().is_confirmed()),
+                    ),
+                    _ => txouts,
+                };
+
+            for (spk_index, full_txout) in txouts {
+                let address =
+                    Address::from_script(&full_txout.txout.script_pubkey, network).unwrap();
+
+                println!(
+                    "{:?} {} {} {} spent:{:?}",
+                    spk_index,
+                    full_txout.txout.value,
+                    full_txout.outpoint,
+                    address,
+                    full_txout.spent_by
+                )
+            }
+        }
+    }
+}
+
+#[allow(clippy::type_complexity)] // FIXME
+pub fn create_tx<P: ChainPosition>(
+    value: u64,
+    address: Address,
+    coin_select: CoinSelectionAlgo,
+    keychain_tracker: &mut KeychainTracker<Keychain, P>,
+    keymap: &HashMap<DescriptorPublicKey, DescriptorSecretKey>,
+) -> Result<(
+    Transaction,
+    Option<(DerivationAdditions<Keychain>, (Keychain, u32))>,
+)> {
+    let mut additions = DerivationAdditions::default();
+
+    let assets = bdk_tmp_plan::Assets {
+        keys: keymap.iter().map(|(pk, _)| pk.clone()).collect(),
+        ..Default::default()
+    };
+
+    // TODO use planning module
+    let mut candidates = planned_utxos(keychain_tracker, &assets).collect::<Vec<_>>();
+
+    // apply coin selection algorithm
+    match coin_select {
+        CoinSelectionAlgo::LargestFirst => {
+            candidates.sort_by_key(|(_, utxo)| Reverse(utxo.txout.value))
+        }
+        CoinSelectionAlgo::SmallestFirst => candidates.sort_by_key(|(_, utxo)| utxo.txout.value),
+        CoinSelectionAlgo::OldestFirst => {
+            candidates.sort_by_key(|(_, utxo)| utxo.chain_position.clone())
+        }
+        CoinSelectionAlgo::NewestFirst => {
+            candidates.sort_by_key(|(_, utxo)| Reverse(utxo.chain_position.clone()))
+        }
+        CoinSelectionAlgo::BranchAndBound => {}
+    }
+
+    // turn the txos we chose into weight and value
+    let wv_candidates = candidates
+        .iter()
+        .map(|(plan, utxo)| {
+            WeightedValue::new(
+                utxo.txout.value,
+                plan.expected_weight() as _,
+                plan.witness_version().is_some(),
+            )
+        })
+        .collect();
+
+    let mut outputs = vec![TxOut {
+        value,
+        script_pubkey: address.script_pubkey(),
+    }];
+
+    let internal_keychain = if keychain_tracker
+        .txout_index
+        .keychains()
+        .get(&Keychain::Internal)
+        .is_some()
+    {
+        Keychain::Internal
+    } else {
+        Keychain::External
+    };
+
+    let ((change_index, change_script), change_additions) = keychain_tracker
+        .txout_index
+        .next_unused_spk(&internal_keychain);
+    additions.append(change_additions);
+
+    // Clone to drop the immutable reference.
+    let change_script = change_script.clone();
+
+    let change_plan = bdk_tmp_plan::plan_satisfaction(
+        &keychain_tracker
+            .txout_index
+            .keychains()
+            .get(&internal_keychain)
+            .expect("must exist")
+            .at_derivation_index(change_index),
+        &assets,
+    )
+    .expect("failed to obtain change plan");
+
+    let mut change_output = TxOut {
+        value: 0,
+        script_pubkey: change_script,
+    };
+
+    let cs_opts = CoinSelectorOpt {
+        target_feerate: 0.5,
+        min_drain_value: keychain_tracker
+            .txout_index
+            .keychains()
+            .get(&internal_keychain)
+            .expect("must exist")
+            .dust_value(),
+        ..CoinSelectorOpt::fund_outputs(
+            &outputs,
+            &change_output,
+            change_plan.expected_weight() as u32,
+        )
+    };
+
+    // TODO: How can we make it easy to shuffle in order of inputs and outputs here?
+    // apply coin selection by saying we need to fund these outputs
+    let mut coin_selector = CoinSelector::new(&wv_candidates, &cs_opts);
+
+    // just select coins in the order provided until we have enough
+    // only use the first result (least waste)
+    let selection = match coin_select {
+        CoinSelectionAlgo::BranchAndBound => {
+            coin_select_bnb(Duration::from_secs(10), coin_selector.clone())
+                .map_or_else(|| coin_selector.select_until_finished(), |cs| cs.finish())?
+        }
+        _ => coin_selector.select_until_finished()?,
+    };
+    let (_, selection_meta) = selection.best_strategy();
+
+    // get the selected utxos
+    let selected_txos = selection.apply_selection(&candidates).collect::<Vec<_>>();
+
+    if let Some(drain_value) = selection_meta.drain_value {
+        change_output.value = drain_value;
+        // if the selection tells us to use change and the change value is sufficient, we add it as an output
+        outputs.push(change_output)
+    }
+
+    let mut transaction = Transaction {
+        version: 0x02,
+        lock_time: keychain_tracker
+            .chain()
+            .latest_checkpoint()
+            .and_then(|block_id| LockTime::from_height(block_id.height).ok())
+            .unwrap_or(LockTime::ZERO)
+            .into(),
+        input: selected_txos
+            .iter()
+            .map(|(_, utxo)| TxIn {
+                previous_output: utxo.outpoint,
+                sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
+                ..Default::default()
+            })
+            .collect(),
+        output: outputs,
+    };
+
+    let prevouts = selected_txos
+        .iter()
+        .map(|(_, utxo)| utxo.txout.clone())
+        .collect::<Vec<_>>();
+    let sighash_prevouts = Prevouts::All(&prevouts);
+
+    // first, set tx values for the plan so that we don't change them while signing
+    for (i, (plan, _)) in selected_txos.iter().enumerate() {
+        if let Some(sequence) = plan.required_sequence() {
+            transaction.input[i].sequence = sequence
+        }
+    }
+
+    // create a short lived transaction
+    let _sighash_tx = transaction.clone();
+    let mut sighash_cache = SighashCache::new(&_sighash_tx);
+
+    for (i, (plan, _)) in selected_txos.iter().enumerate() {
+        let requirements = plan.requirements();
+        let mut auth_data = bdk_tmp_plan::SatisfactionMaterial::default();
+        assert!(
+            !requirements.requires_hash_preimages(),
+            "can't have hash pre-images since we didn't provide any."
+        );
+        assert!(
+            requirements.signatures.sign_with_keymap(
+                i,
+                keymap,
+                &sighash_prevouts,
+                None,
+                None,
+                &mut sighash_cache,
+                &mut auth_data,
+                &Secp256k1::default(),
+            )?,
+            "we should have signed with this input."
+        );
+
+        match plan.try_complete(&auth_data) {
+            bdk_tmp_plan::PlanState::Complete {
+                final_script_sig,
+                final_script_witness,
+            } => {
+                if let Some(witness) = final_script_witness {
+                    transaction.input[i].witness = witness;
+                }
+
+                if let Some(script_sig) = final_script_sig {
+                    transaction.input[i].script_sig = script_sig;
+                }
+            }
+            bdk_tmp_plan::PlanState::Incomplete(_) => {
+                return Err(anyhow!(
+                    "we weren't able to complete the plan with our keys."
+                ));
+            }
+        }
+    }
+
+    let change_info = if selection_meta.drain_value.is_some() {
+        Some((additions, (internal_keychain, change_index)))
+    } else {
+        None
+    };
+
+    Ok((transaction, change_info))
+}
+
+pub fn handle_commands<C: clap::Subcommand, P>(
+    command: Commands<C>,
+    broadcast: impl FnOnce(&Transaction) -> Result<()>,
+    // we Mutex around these not because we need them for a simple CLI app but to demonstrate how
+    // all the stuff we're doing can be made thread-safe and not keep locks up over an IO bound.
+    tracker: &Mutex<KeychainTracker<Keychain, P>>,
+    store: &Mutex<KeychainStore<Keychain, P>>,
+    network: Network,
+    keymap: &HashMap<DescriptorPublicKey, DescriptorSecretKey>,
+) -> Result<()>
+where
+    P: ChainPosition,
+    KeychainChangeSet<Keychain, P>: serde::Serialize + serde::de::DeserializeOwned,
+{
+    match command {
+        // TODO: Make these functions return stuffs
+        Commands::Address { addr_cmd } => run_address_cmd(tracker, store, addr_cmd, network),
+        Commands::Balance => {
+            run_balance_cmd(tracker);
+            Ok(())
+        }
+        Commands::TxOut { txout_cmd } => {
+            run_txo_cmd(txout_cmd, tracker, network);
+            Ok(())
+        }
+        Commands::Send {
+            value,
+            address,
+            coin_select,
+        } => {
+            let (transaction, change_index) = {
+                // take mutable ref to construct tx -- it is only open for a short time while building it.
+                let tracker = &mut *tracker.lock().unwrap();
+                let (transaction, change_info) =
+                    create_tx(value, address, coin_select, tracker, keymap)?;
+
+                if let Some((change_derivation_changes, (change_keychain, index))) = change_info {
+                    // We must first persist to disk the fact that we've got a new address from the
+                    // change keychain so future scans will find the tx we're about to broadcast.
+                    // If we're unable to persist this, then we don't want to broadcast.
+                    let store = &mut *store.lock().unwrap();
+                    store.append_changeset(&change_derivation_changes.into())?;
+
+                    // We don't want other callers/threads to use this address while we're using it
+                    // but we also don't want to scan the tx we just created because it's not
+                    // technically in the blockchain yet.
+                    tracker.txout_index.mark_used(&change_keychain, index);
+                    (transaction, Some((change_keychain, index)))
+                } else {
+                    (transaction, None)
+                }
+            };
+
+            match (broadcast)(&transaction) {
+                Ok(_) => {
+                    println!("Broadcasted Tx : {}", transaction.txid());
+                    let mut tracker = tracker.lock().unwrap();
+                    match tracker.insert_tx(transaction.clone(), P::unconfirmed()) {
+                        Ok(changeset) => {
+                            let store = &mut *store.lock().unwrap();
+                            // We know the tx is at least unconfirmed now. Note if persisting here fails,
+                            // it's not a big deal since we can always find it again form
+                            // blockchain.
+                            store.append_changeset(&changeset)?;
+                            Ok(())
+                        }
+                        Err(e) => match e {
+                            InsertTxError::Chain(e) => match e {
+                                // TODO: add insert_unconfirmed_tx to the chaingraph and sparsechain
+                                sparse_chain::InsertTxError::TxTooHigh { .. } => unreachable!("we are inserting at unconfirmed position"),
+                                sparse_chain::InsertTxError::TxMovedUnexpectedly { txid, original_pos, ..} => Err(anyhow!("the tx we created {} has already been confirmed at block {:?}", txid, original_pos)),
+                            },
+                            InsertTxError::UnresolvableConflict(e) => Err(e).context("another tx that conflicts with the one we tried to create has been confirmed"),
+                        }
+                    }
+                }
+                Err(e) => {
+                    let tracker = &mut *tracker.lock().unwrap();
+                    if let Some((keychain, index)) = change_index {
+                        // We failed to broadcast, so allow our change address to be used in the future
+                        tracker.txout_index.unmark_used(&keychain, index);
+                    }
+                    Err(e)
+                }
+            }
+        }
+        Commands::ChainSpecific(_) => {
+            todo!("example code is meant to handle this!")
+        }
+    }
+}
+
+#[allow(clippy::type_complexity)] // FIXME
+pub fn init<C: clap::Subcommand, P>() -> anyhow::Result<(
+    Args<C>,
+    KeyMap,
+    // These don't need to have mutexes around them, but we want the cli example code to make it obvious how they
+    // are thread-safe, forcing the example developers to show where they would lock and unlock things.
+    Mutex<KeychainTracker<Keychain, P>>,
+    Mutex<KeychainStore<Keychain, P>>,
+)>
+where
+    P: sparse_chain::ChainPosition,
+    KeychainChangeSet<Keychain, P>: serde::Serialize + serde::de::DeserializeOwned,
+{
+    let args = Args::<C>::parse();
+    let secp = Secp256k1::default();
+    let (descriptor, mut keymap) =
+        Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, &args.descriptor)?;
+
+    let mut tracker = KeychainTracker::default();
+    tracker.set_checkpoint_limit(Some(args.cp_limit));
+
+    tracker
+        .txout_index
+        .add_keychain(Keychain::External, descriptor);
+
+    let internal = args
+        .change_descriptor
+        .clone()
+        .map(|descriptor| Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, &descriptor))
+        .transpose()?;
+    if let Some((internal_descriptor, internal_keymap)) = internal {
+        keymap.extend(internal_keymap);
+        tracker
+            .txout_index
+            .add_keychain(Keychain::Internal, internal_descriptor);
+    };
+
+    let mut db = KeychainStore::<Keychain, P>::new_from_path(args.db_path.as_path())?;
+
+    if let Err(e) = db.load_into_keychain_tracker(&mut tracker) {
+        match tracker.chain().latest_checkpoint()  {
+            Some(checkpoint) => eprintln!("Failed to load all changesets from {}. Last checkpoint was at height {}. Error: {}", args.db_path.display(), checkpoint.height, e),
+            None => eprintln!("Failed to load any checkpoints from {}: {}", args.db_path.display(), e),
+
+        }
+        eprintln!("⚠ Consider running a rescan of chain data.");
+    }
+
+    Ok((args, keymap, Mutex::new(tracker), Mutex::new(db)))
+}
+
+pub fn planned_utxos<'a, AK: bdk_tmp_plan::CanDerive + Clone, P: ChainPosition>(
+    tracker: &'a KeychainTracker<Keychain, P>,
+    assets: &'a bdk_tmp_plan::Assets<AK>,
+) -> impl Iterator<Item = (bdk_tmp_plan::Plan<AK>, FullTxOut<P>)> + 'a {
+    tracker
+        .full_utxos()
+        .filter_map(move |((keychain, derivation_index), full_txout)| {
+            Some((
+                bdk_tmp_plan::plan_satisfaction(
+                    &tracker
+                        .txout_index
+                        .keychains()
+                        .get(keychain)
+                        .expect("must exist since we have a utxo for it")
+                        .at_derivation_index(*derivation_index),
+                    assets,
+                )?,
+                full_txout,
+            ))
+        })
+}
--- a/example-crates/wallet_electrum/Cargo.toml
+++ b/example-crates/wallet_electrum/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "wallet_electrum_example"
-version = "0.2.0"
+version = "0.1.0"
 edition = "2021"

 [dependencies]
--- a/example-crates/wallet_electrum/src/main.rs
+++ b/example-crates/wallet_electrum/src/main.rs
@@ -1,21 +1,24 @@
-const DB_MAGIC: &str = "bdk_wallet_electrum_example";
+use std::{io::Write, str::FromStr};
+
+use bdk::{
+    bitcoin::{Address, Network},
+    SignOptions, Wallet,
+};
+use bdk_electrum::{
+    electrum_client::{self, ElectrumApi},
+    ElectrumExt,
+};
+use bdk_file_store::KeychainStore;
+
 const SEND_AMOUNT: u64 = 5000;
 const STOP_GAP: usize = 50;
 const BATCH_SIZE: usize = 5;

-use std::io::Write;
-use std::str::FromStr;
-
-use bdk::bitcoin::Address;
-use bdk::SignOptions;
-use bdk::{bitcoin::Network, Wallet};
-use bdk_electrum::electrum_client::{self, ElectrumApi};
-use bdk_electrum::ElectrumExt;
-use bdk_file_store::Store;
-
 fn main() -> Result<(), Box<dyn std::error::Error>> {
+    println!("Hello, world!");
+
    let db_path = std::env::temp_dir().join("bdk-electrum-example");
-    let db = Store::<bdk::wallet::ChangeSet>::new_from_path(DB_MAGIC.as_bytes(), db_path)?;
+    let db = KeychainStore::new_from_path(db_path)?;
    let external_descriptor = "wpkh(tprv8ZgxMBicQKsPdy6LMhUtFHAgpocR8GC6QmwMSFpZs7h6Eziw3SpThFfczTDh5rW2krkqffa11UpX3XkeTTB2FvzZKWXqPY54Y6Rq4AQ5R8L/84'/0'/0'/0/*)";
    let internal_descriptor = "wpkh(tprv8ZgxMBicQKsPdy6LMhUtFHAgpocR8GC6QmwMSFpZs7h6Eziw3SpThFfczTDh5rW2krkqffa11UpX3XkeTTB2FvzZKWXqPY54Y6Rq4AQ5R8L/84'/0'/0'/1/*)";

@@ -33,33 +36,41 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
    println!("Wallet balance before syncing: {} sats", balance.total());

    print!("Syncing...");
-    let client = electrum_client::Client::new("ssl://electrum.blockstream.info:60002")?;
-
+    // Scanning the chain...
+    let electrum_url = "ssl://electrum.blockstream.info:60002";
+    let client = electrum_client::Client::new(electrum_url)?;
    let local_chain = wallet.checkpoints();
-    let keychain_spks = wallet
+    let spks = wallet
        .spks_of_all_keychains()
        .into_iter()
-        .map(|(k, k_spks)| {
-            let mut once = Some(());
-            let mut stdout = std::io::stdout();
-            let k_spks = k_spks
-                .inspect(move |(spk_i, _)| match once.take() {
-                    Some(_) => print!("\nScanning keychain [{:?}]", k),
-                    None => print!(" {:<3}", spk_i),
-                })
-                .inspect(move |_| stdout.flush().expect("must flush"));
-            (k, k_spks)
+        .map(|(k, spks)| {
+            let mut first = true;
+            (
+                k,
+                spks.inspect(move |(spk_i, _)| {
+                    if first {
+                        first = false;
+                        print!("\nScanning keychain [{:?}]:", k);
+                    }
+                    print!(" {}", spk_i);
+                    let _ = std::io::stdout().flush();
+                }),
+            )
        })
        .collect();
-
-    let electrum_update =
-        client.scan(local_chain, keychain_spks, None, None, STOP_GAP, BATCH_SIZE)?;
-
+    let electrum_update = client
+        .scan(
+            local_chain,
+            spks,
+            core::iter::empty(),
+            core::iter::empty(),
+            STOP_GAP,
+            BATCH_SIZE,
+        )?
+        .into_confirmation_time_update(&client)?;
    println!();
-
-    let missing = electrum_update.missing_full_txs(wallet.as_ref());
-    let update = electrum_update.finalize_as_confirmation_time(&client, None, missing)?;
-
+    let new_txs = client.batch_transaction_get(electrum_update.missing_full_txs(&wallet))?;
+    let update = electrum_update.into_keychain_scan(new_txs, &wallet)?;
    wallet.apply_update(update)?;
    wallet.commit()?;

--- a/example-crates/wallet_esplora/Cargo.toml
+++ b/example-crates/wallet_esplora/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
-name = "wallet_esplora"
-version = "0.2.0"
+name = "bdk-esplora-wallet-example"
+version = "0.1.0"
 edition = "2021"
 publish = false

--- a/example-crates/wallet_esplora/src/main.rs
+++ b/example-crates/wallet_esplora/src/main.rs
@@ -1,21 +1,20 @@
-const DB_MAGIC: &str = "bdk_wallet_esplora_example";
-const SEND_AMOUNT: u64 = 5000;
-const STOP_GAP: usize = 50;
-const PARALLEL_REQUESTS: usize = 5;
-
-use std::{io::Write, str::FromStr};
-
 use bdk::{
    bitcoin::{Address, Network},
    wallet::AddressIndex,
    SignOptions, Wallet,
 };
-use bdk_esplora::{esplora_client, EsploraExt};
-use bdk_file_store::Store;
+use bdk_esplora::esplora_client;
+use bdk_esplora::EsploraExt;
+use bdk_file_store::KeychainStore;
+use std::{io::Write, str::FromStr};
+
+const SEND_AMOUNT: u64 = 5000;
+const STOP_GAP: usize = 50;
+const PARALLEL_REQUESTS: usize = 5;

 fn main() -> Result<(), Box<dyn std::error::Error>> {
    let db_path = std::env::temp_dir().join("bdk-esplora-example");
-    let db = Store::<bdk::wallet::ChangeSet>::new_from_path(DB_MAGIC.as_bytes(), db_path)?;
+    let db = KeychainStore::new_from_path(db_path)?;
    let external_descriptor = "wpkh(tprv8ZgxMBicQKsPdy6LMhUtFHAgpocR8GC6QmwMSFpZs7h6Eziw3SpThFfczTDh5rW2krkqffa11UpX3XkeTTB2FvzZKWXqPY54Y6Rq4AQ5R8L/84'/0'/0'/0/*)";
    let internal_descriptor = "wpkh(tprv8ZgxMBicQKsPdy6LMhUtFHAgpocR8GC6QmwMSFpZs7h6Eziw3SpThFfczTDh5rW2krkqffa11UpX3XkeTTB2FvzZKWXqPY54Y6Rq4AQ5R8L/84'/0'/0'/1/*)";

@@ -33,30 +32,33 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
    println!("Wallet balance before syncing: {} sats", balance.total());

    print!("Syncing...");
-    let client =
-        esplora_client::Builder::new("https://blockstream.info/testnet/api").build_blocking()?;
-
-    let local_chain = wallet.checkpoints();
-    let keychain_spks = wallet
+    // Scanning the chain...
+    let esplora_url = "https://mempool.space/testnet/api";
+    let client = esplora_client::Builder::new(esplora_url).build_blocking()?;
+    let checkpoints = wallet.checkpoints();
+    let spks = wallet
        .spks_of_all_keychains()
        .into_iter()
-        .map(|(k, k_spks)| {
-            let mut once = Some(());
-            let mut stdout = std::io::stdout();
-            let k_spks = k_spks
-                .inspect(move |(spk_i, _)| match once.take() {
-                    Some(_) => print!("\nScanning keychain [{:?}]", k),
-                    None => print!(" {:<3}", spk_i),
-                })
-                .inspect(move |_| stdout.flush().expect("must flush"));
-            (k, k_spks)
+        .map(|(k, spks)| {
+            let mut first = true;
+            (
+                k,
+                spks.inspect(move |(spk_i, _)| {
+                    if first {
+                        first = false;
+                        print!("\nScanning keychain [{:?}]:", k);
+                    }
+                    print!(" {}", spk_i);
+                    let _ = std::io::stdout().flush();
+                }),
+            )
        })
        .collect();
    let update = client.scan(
-        local_chain,
-        keychain_spks,
-        None,
-        None,
+        checkpoints,
+        spks,
+        core::iter::empty(),
+        core::iter::empty(),
        STOP_GAP,
        PARALLEL_REQUESTS,
    )?;
--- a/example-crates/wallet_esplora_async/Cargo.toml
+++ b/example-crates/wallet_esplora_async/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "wallet_esplora_async"
-version = "0.2.0"
+version = "0.1.0"
 edition = "2021"

 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
--- a/example-crates/wallet_esplora_async/src/main.rs
+++ b/example-crates/wallet_esplora_async/src/main.rs
@@ -6,17 +6,16 @@ use bdk::{
    SignOptions, Wallet,
 };
 use bdk_esplora::{esplora_client, EsploraAsyncExt};
-use bdk_file_store::Store;
+use bdk_file_store::KeychainStore;

-const DB_MAGIC: &str = "bdk_wallet_esplora_async_example";
 const SEND_AMOUNT: u64 = 5000;
 const STOP_GAP: usize = 50;
 const PARALLEL_REQUESTS: usize = 5;

 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let db_path = std::env::temp_dir().join("bdk-esplora-async-example");
-    let db = Store::<bdk::wallet::ChangeSet>::new_from_path(DB_MAGIC.as_bytes(), db_path)?;
+    let db_path = std::env::temp_dir().join("bdk-esplora-example");
+    let db = KeychainStore::new_from_path(db_path)?;
    let external_descriptor = "wpkh(tprv8ZgxMBicQKsPdy6LMhUtFHAgpocR8GC6QmwMSFpZs7h6Eziw3SpThFfczTDh5rW2krkqffa11UpX3XkeTTB2FvzZKWXqPY54Y6Rq4AQ5R8L/84'/0'/0'/0/*)";
    let internal_descriptor = "wpkh(tprv8ZgxMBicQKsPdy6LMhUtFHAgpocR8GC6QmwMSFpZs7h6Eziw3SpThFfczTDh5rW2krkqffa11UpX3XkeTTB2FvzZKWXqPY54Y6Rq4AQ5R8L/84'/0'/0'/1/*)";

@@ -34,31 +33,34 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
    println!("Wallet balance before syncing: {} sats", balance.total());

    print!("Syncing...");
-    let client =
-        esplora_client::Builder::new("https://blockstream.info/testnet/api").build_async()?;
-
-    let local_chain = wallet.checkpoints();
-    let keychain_spks = wallet
+    // Scanning the blockchain
+    let esplora_url = "https://mempool.space/testnet/api";
+    let client = esplora_client::Builder::new(esplora_url).build_async()?;
+    let checkpoints = wallet.checkpoints();
+    let spks = wallet
        .spks_of_all_keychains()
        .into_iter()
-        .map(|(k, k_spks)| {
-            let mut once = Some(());
-            let mut stdout = std::io::stdout();
-            let k_spks = k_spks
-                .inspect(move |(spk_i, _)| match once.take() {
-                    Some(_) => print!("\nScanning keychain [{:?}]", k),
-                    None => print!(" {:<3}", spk_i),
-                })
-                .inspect(move |_| stdout.flush().expect("must flush"));
-            (k, k_spks)
+        .map(|(k, spks)| {
+            let mut first = true;
+            (
+                k,
+                spks.inspect(move |(spk_i, _)| {
+                    if first {
+                        first = false;
+                        print!("\nScanning keychain [{:?}]:", k);
+                    }
+                    print!(" {}", spk_i);
+                    let _ = std::io::stdout().flush();
+                }),
+            )
        })
        .collect();
    let update = client
        .scan(
-            local_chain,
-            keychain_spks,
-            [],
-            [],
+            checkpoints,
+            spks,
+            std::iter::empty(),
+            std::iter::empty(),
            STOP_GAP,
            PARALLEL_REQUESTS,
        )
Author	SHA1	Message	Date
Steve Myers	747866579d	Add description to file_store cargo metadata	2023-03-20 12:45:33 -05:00
Steve Myers	e6387f8f27	Remove keyword from file_store cargo metadata	2023-03-20 12:37:22 -05:00
				`@@ -0,0 +1 @@`
				Provides common command line processing logic between examples using the `KeychainTracker`