From 10a55183a188e5fed4c2b5800d8867a980c6d383 Mon Sep 17 00:00:00 2001
From: hunicus <93150691+hunicus@users.noreply.github.com>
Date: Sun, 13 Nov 2022 22:36:46 -0500
Subject: [PATCH] Add faq: why timestamps don't always increase

---
 frontend/src/app/docs/api-docs/api-docs-data.ts        | 7 +++++++
 frontend/src/app/docs/api-docs/api-docs.component.html | 4 ++++
 2 files changed, 11 insertions(+)

diff --git a/frontend/src/app/docs/api-docs/api-docs-data.ts b/frontend/src/app/docs/api-docs/api-docs-data.ts
index 970d6ab73..9b2fcac4b 100644
--- a/frontend/src/app/docs/api-docs/api-docs-data.ts
+++ b/frontend/src/app/docs/api-docs/api-docs-data.ts
@@ -8653,6 +8653,13 @@ export const faqData = [
     fragment: "why-empty-blocks",
     title: "Why are there empty blocks?",
   },
+  {
+    type: "endpoint",
+    category: "advanced",
+    showConditions: bitcoinNetworks,
+    fragment: "why-block-timestamps-dont-always-increase",
+    title: "Why don't block timestamps always increase?",
+  },
   {
     type: "category",
     category: "self-hosting",
diff --git a/frontend/src/app/docs/api-docs/api-docs.component.html b/frontend/src/app/docs/api-docs/api-docs.component.html
index 9fc9aa8a0..35fe40362 100644
--- a/frontend/src/app/docs/api-docs/api-docs.component.html
+++ b/frontend/src/app/docs/api-docs/api-docs.component.html
@@ -203,6 +203,10 @@
   <p>When a new block is found, mining pools send miners a block template with no transactions so they can start searching for the next block as soon as possible. They send a block template full of transactions right afterward, but a full block template is a bigger data transfer and takes slightly longer to reach miners.</p><p>In this intervening time, which is usually no more than 1-2 seconds, miners sometimes get lucky and find a new block using the empty block template.</p>
 </ng-template>
 
+<ng-template type="why-block-timestamps-dont-always-increase">
+  <p>Block validation rules do not strictly require that a block's timestamp be more recent than the timestamp of the block preceding it. Without a central authority, it's impossible to know what the exact correct time is. Instead, the Bitcoin protocol requires that a block's timestamp meet certain requirements. One of those requirements is that a block's timestamp cannot be older than the median timestamp of the 12 blocks that came before it. See more details <a href="https://en.bitcoin.it/wiki/Block_timestamp" target="_blank">here</a>.</p><p>As a result, timestamps are only accurate to within an hour or so, which sometimes results in blocks with timestamps that appear out of order.</p>
+</ng-template>
+
 <ng-template type="who-runs-this-website">
   The official mempool.space website is operated by The Mempool Open Source Project. See more information on our <a [routerLink]="['/about']">About page</a>. There are also many unofficial instances of this website operated by individual members of the Bitcoin community.
 </ng-template>