diff --git a/AGENTS.md b/AGENTS.md
index 62505ce..003b8e8 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -223,7 +223,17 @@ bun run test:server
 ```
 Tests require the server running. The test script starts the server, runs tests, then stops it.
 
+## Version Management
+
+Version is managed via `VERSION.txt` (single source of truth). All other version references (`backend/package.json`, `frontend/package.json`, `backend/src/index.ts`) use placeholder `{{VERSION}}` and are replaced at build time.
+
+### Versioning Rules
+- Bump micro version (0.1.x) on every commit
+- Update `VERSION.txt` before committing
+- Never commit actual version numbers in source files
+
 ## Version History
+- 0.1.2: VERSION.txt build-time injection, docs nav fixes, blog link
 - 0.1.1: System default AI configuration via env vars, "Use system default" checkbox in settings
 - 0.1.0: Automatic geolocation capture, Starlight documentation site
 - 0.0.6: Automatic geolocation capture on event creation, reverse geocoding to place names
diff --git a/Dockerfile b/Dockerfile
index 3ab471c..8b15c93 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,9 @@
 # Multi-stage build: Backend + Frontend
+FROM alpine:latest AS version
+COPY VERSION.txt /tmp/version.txt
+
 FROM oven/bun:1.1-alpine AS backend-builder
+COPY --from=version /tmp/version.txt /tmp/version.txt
 
 WORKDIR /app/backend
 COPY backend/package*.json ./
@@ -7,11 +11,13 @@ RUN bun install
 COPY backend/prisma ./prisma
 RUN bunx prisma generate
 COPY backend/src ./src
-RUN bun build src/index.ts --outdir ./dist --target bun
+COPY backend/package.json ./
+RUN sed -i "s/{{VERSION}}/$(cat /tmp/version.txt)/g" src/index.ts && sed -i "s/{{VERSION}}/$(cat /tmp/version.txt)/g" package.json && bun build src/index.ts --outdir ./dist --target bun
 
 FROM node:20-alpine AS frontend-builder
 ARG VITE_GIT_URL=https://git.kropa.tech/lotherk/deardiary
 ARG VITE_WEBSITE_URL=https://deardiary.lother.io
+COPY --from=backend-builder /tmp/version.txt /tmp/version.txt
 
 WORKDIR /app/frontend
 COPY frontend/package*.json ./
@@ -19,7 +25,7 @@ RUN npm install
 COPY frontend ./
 ENV VITE_GIT_URL=$VITE_GIT_URL
 ENV VITE_WEBSITE_URL=$VITE_WEBSITE_URL
-RUN npm run build
+RUN sed -i "s/{{VERSION}}/$(cat /tmp/version.txt)/g" package.json && npm run build
 
 FROM oven/bun:1.1-alpine AS runner
 
diff --git a/VERSION.txt b/VERSION.txt
new file mode 100644
index 0000000..8294c18
--- /dev/null
+++ b/VERSION.txt
@@ -0,0 +1 @@
+0.1.2
\ No newline at end of file
diff --git a/backend/package.json b/backend/package.json
index 403635c..0e1e334 100644
--- a/backend/package.json
+++ b/backend/package.json
@@ -1,6 +1,6 @@
 {
   "name": "deardiary-backend",
-  "version": "0.0.3",
+  "version": "{{VERSION}}",
   "type": "module",
   "scripts": {
     "dev": "bun --watch src/index.ts",
diff --git a/backend/src/index.ts b/backend/src/index.ts
index 6129bd1..d54bfdb 100644
--- a/backend/src/index.ts
+++ b/backend/src/index.ts
@@ -726,7 +726,7 @@ app.post('/api/v1/ai/test', async (c) => {
   }
 });
 
-const DEARDIARY_VERSION = '0.1.0';
+const DEARDIARY_VERSION = '{{VERSION}}';
 const MIN_IMPORT_VERSION = '0.0.3';
 
 interface ExportData {
diff --git a/build-version.sh b/build-version.sh
new file mode 100755
index 0000000..c53ed28
--- /dev/null
+++ b/build-version.sh
@@ -0,0 +1,22 @@
+#!/bin/bash
+# Build script: injects version from VERSION.txt into all build-time locations
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+ROOT_DIR="$SCRIPT_DIR"
+
+VERSION=$(cat "$ROOT_DIR/VERSION.txt")
+
+echo "Injecting version $VERSION..."
+
+# Backend version constant
+sed -i "s/const DEARDIARY_VERSION = '[^']*'/const DEARDIARY_VERSION = '$VERSION'/" "$ROOT_DIR/backend/src/index.ts"
+
+# Backend package.json
+sed -i "s/\"version\": \"[^\"]*\"/\"version\": \"$VERSION\"/" "$ROOT_DIR/backend/package.json"
+
+# Frontend package.json  
+sed -i "s/\"version\": \"[^\"]*\"/\"version\": \"$VERSION\"/" "$ROOT_DIR/frontend/package.json"
+
+echo "Done."
diff --git a/frontend/package.json b/frontend/package.json
index c86aba5..3d1bb1f 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -1,7 +1,7 @@
 {
   "name": "deardiary-frontend",
   "private": true,
-  "version": "0.1.0",
+  "version": "{{VERSION}}",
   "type": "module",
   "scripts": {
     "dev": "vite",