diff --git a/.forgejo/workflows/build-ext.yml b/.forgejo/workflows/build-ext.yml
new file mode 100644
index 0000000..03bea22
--- /dev/null
+++ b/.forgejo/workflows/build-ext.yml
@@ -0,0 +1,23 @@
+name: Build extension ZIP
+
+on:
+  push:
+    branches: ['main']
+    paths:
+      - 'extension/**/*'
+
+jobs:
+  publish:
+    name: Build extension
+    runs-on: docker
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Build extension
+        runs: ./build-ext.sh
+      - name: Upload extension
+        actions/upload-artifact@v4
+        with:
+          name: aci-ext.zip
+          path: aci-ext.zip
diff --git a/.forgejo/workflows/publish.yml b/.forgejo/workflows/publish.yml
index 786bf3f..2df7ab4 100644
--- a/.forgejo/workflows/publish.yml
+++ b/.forgejo/workflows/publish.yml
@@ -3,6 +3,8 @@ name: Publish docker image
 on:
   push:
     branches: ['main']
+    paths:
+      - 'backend/**/*'
 
 jobs:
   publish:
diff --git a/.gitignore b/.gitignore
index a631881..a6756ed 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@ __pycache__/
 .direnv/
 result
 checkin.db
+aci-*.zip
diff --git a/build-ext.sh b/build-ext.sh
new file mode 100755
index 0000000..4e0e1db
--- /dev/null
+++ b/build-ext.sh
@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+set -uex pipefail
+
+cd extension/
+echo "Building ZIP..."
+zip -- -r -FS ../aci-ext.zip *
+cd ../