diff --git a/.githooks/bump-version.mjs b/.githooks/bump-version.mjs
new file mode 100644
index 0000000..180584b
--- /dev/null
+++ b/.githooks/bump-version.mjs
@@ -0,0 +1,54 @@
+// Pre-commit version bump. The app version lives in mykindlebox/client/
+// package.json (shown in the sidebar footer); the server package is kept on
+// the same number. Every commit that touches the app bumps the patch number
+// (1.4.2 → 1.4.3) and stages the change, so each commit is a distinct version.
+//
+// A hand-made minor/major bump (`npm version minor --no-git-tag-version` in
+// client/) is kept as-is instead of being bumped again, and copied to the
+// server package.
+//
+// Skipped entirely when nothing under mykindlebox/ is staged (docs-only
+// commits) or SKIP_VERSION_BUMP=1 is set.
+import { execFileSync } from 'node:child_process'
+import { readFileSync, writeFileSync } from 'node:fs'
+
+const PACKAGES = ['mykindlebox/client', 'mykindlebox/server']
+
+function git(...args) {
+  return execFileSync('git', args, { encoding: 'utf8' })
+}
+
+function versionAt(ref) {
+  try {
+    return JSON.parse(git('show', `${ref}:mykindlebox/client/package.json`)).version
+  } catch {
+    return null // no HEAD yet, or the file didn't exist
+  }
+}
+
+if (process.env.SKIP_VERSION_BUMP === '1') process.exit(0)
+
+const staged = git('diff', '--cached', '--name-only').split('\n').filter(Boolean)
+if (!staged.some((file) => file.startsWith('mykindlebox/'))) process.exit(0)
+
+const headVersion = versionAt('HEAD')
+const stagedVersion = versionAt('') // `git show :path` reads the index
+const manualBump = Boolean(headVersion && stagedVersion && headVersion !== stagedVersion)
+
+const [major, minor, patch] = (stagedVersion ?? '0.0.0').split('.').map(Number)
+const next = manualBump ? stagedVersion : `${major}.${minor}.${patch + 1}`
+
+// Also brings the server (and lockfiles) along after a client-only manual bump.
+for (const dir of PACKAGES) {
+  for (const name of ['package.json', 'package-lock.json']) {
+    const path = `${dir}/${name}`
+    const json = JSON.parse(readFileSync(path, 'utf8'))
+    if (json.version === next && (!json.packages?.[''] || json.packages[''].version === next)) continue
+    json.version = next
+    if (json.packages?.['']) json.packages[''].version = next
+    writeFileSync(path, `${JSON.stringify(json, null, 2)}\n`)
+    git('add', path)
+  }
+}
+
+console.log(`MyKindlebox version ${manualBump ? 'set' : 'bumped'} to ${next}`)
diff --git a/.githooks/pre-commit b/.githooks/pre-commit
new file mode 100644
index 0000000..c3df700
--- /dev/null
+++ b/.githooks/pre-commit
@@ -0,0 +1,4 @@
+#!/bin/sh
+# Bumps the app's patch version on every commit that touches mykindlebox/.
+# Enabled per clone with: git config core.hooksPath .githooks
+exec node "$(git rev-parse --show-toplevel)/.githooks/bump-version.mjs"
diff --git a/CLAUDE.md b/CLAUDE.md
index c7540b9..97fb8d4 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -35,6 +35,7 @@ Deployment: `docker compose up --build` from `mykindlebox/` serves the app on po
 ### Conventions
 
 - The REST API speaks **snake_case** at the boundary; Drizzle columns are camelCase. `server/utils/case.ts` converts both directions — don't hand-write conversions.
+- **Versioning**: the app version is `mykindlebox/client/package.json`'s `version` (server package kept in sync), shown at the bottom of the sidebar and the mobile More menu. The checked-in pre-commit hook `.githooks/bump-version.mjs` bumps the patch number on every commit that touches `mykindlebox/` — don't bump patch versions by hand. For a minor/major release, run `npm version minor --no-git-tag-version` (or `major`) in `client/` before committing; the hook keeps it and syncs the server. Each clone must enable the hook once with `git config core.hooksPath .githooks`.
 - The client talks to the API over **relative URLs** (`/api`, `/uploads`). Never reintroduce a hardcoded `http://localhost:3001`; it breaks LAN/PWA access from other devices.
 
 ## What MyKindlebox is
diff --git a/mykindlebox/client/package-lock.json b/mykindlebox/client/package-lock.json
index 772d00c..084ff44 100644
--- a/mykindlebox/client/package-lock.json
+++ b/mykindlebox/client/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "client",
-  "version": "0.0.0",
+  "version": "1.0.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "client",
-      "version": "0.0.0",
+      "version": "1.0.0",
       "dependencies": {
         "@tanstack/react-query": "^5.101.0",
         "react": "^19.2.6",
diff --git a/mykindlebox/client/package.json b/mykindlebox/client/package.json
index a7d4484..c14f5a3 100644
--- a/mykindlebox/client/package.json
+++ b/mykindlebox/client/package.json
@@ -1,7 +1,7 @@
 {
   "name": "client",
   "private": true,
-  "version": "0.0.0",
+  "version": "1.0.0",
   "type": "module",
   "scripts": {
     "dev": "vite",
diff --git a/mykindlebox/client/src/components/Layout.jsx b/mykindlebox/client/src/components/Layout.jsx
index e1713cd..1f057b5 100644
--- a/mykindlebox/client/src/components/Layout.jsx
+++ b/mykindlebox/client/src/components/Layout.jsx
@@ -1,6 +1,9 @@
 import { useEffect, useRef, useState } from 'react'
 import { NavLink, Outlet, useLocation } from 'react-router-dom'
 import QuickSearch from './QuickSearch'
+// Vite inlines just this field; it's bumped by the pre-commit hook
+// (.githooks/bump-version.mjs) on every commit that touches the app.
+import { version as APP_VERSION } from '../../package.json'
 
 // Stroke icons shared by the sidebar and the mobile bottom nav. Kept inline
 // (no icon library) to match the other hand-rolled SVGs in the app.
@@ -173,6 +176,9 @@ function MoreMenu() {
               {item.label}
             </NavLink>
           ))}
+          <p className="border-t border-border px-3 pb-1 pt-2 font-body text-xs text-text-secondary">
+            MyKindlebox v{APP_VERSION}
+          </p>
         </div>
       )}
     </div>
@@ -207,6 +213,7 @@ function Layout() {
             </NavLink>
           ))}
         </nav>
+        <p className="mt-auto px-3 font-body text-xs text-text-secondary">v{APP_VERSION}</p>
       </aside>
 
       {/* min-w-0 lets wide children (tables, the pedigree tree) scroll inside