diff --git a/.gitea/workflows/build.yml b/.gitea/workflows/build.yml
new file mode 100644
index 0000000..aabb884
--- /dev/null
+++ b/.gitea/workflows/build.yml
@@ -0,0 +1,87 @@
+name: build
+
+on:
+  push:
+    branches: [main]
+    tags: ['v*']
+
+env:
+  REGISTRY: harbor.pmagnus.cloud
+  IMAGE: harbor.pmagnus.cloud/btcprice/btcprice
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.13'
+          cache: pip
+          cache-dependency-path: |
+            requirements.txt
+            requirements-dev.txt
+
+      - name: Test
+        run: |
+          python -m pip install -r requirements-dev.txt
+          python -m pytest tests/
+
+      - name: Generate immutable tags
+        id: tags
+        shell: bash
+        run: |
+          set -euo pipefail
+          SHA=$(git rev-parse --short HEAD)
+          case "$GITHUB_REF" in
+            refs/tags/v*) VERSION="${GITHUB_REF_NAME#v}" ;;
+            *) VERSION="main-$(date -u +%Y%m%d%H%M%S)" ;;
+          esac
+          echo "sha=$SHA" >> "$GITHUB_OUTPUT"
+          echo "primary=$IMAGE:$VERSION" >> "$GITHUB_OUTPUT"
+          echo "qualified=$IMAGE:$VERSION-$SHA" >> "$GITHUB_OUTPUT"
+
+      # anvil is not a NetBird peer. Host networking makes BuildKit use the
+      # runner host's pinned Harbor address; keep this until anvil is enrolled.
+      - uses: docker/setup-buildx-action@v3
+        with:
+          driver-opts: network=host
+
+      - uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ secrets.HARBOR_ROBOT_USER }}
+          password: ${{ secrets.HARBOR_ROBOT_TOKEN }}
+
+      - uses: docker/build-push-action@v6
+        with:
+          context: .
+          platforms: linux/amd64
+          push: true
+          # Harbor blocks manifest reads until Trivy has approved the image.
+          # Push one tag first, then add the companion tag after the scan.
+          tags: ${{ steps.tags.outputs.primary }}
+          build-args: |
+            BUILD_SHA=${{ steps.tags.outputs.sha }}
+          cache-from: type=registry,ref=${{ env.IMAGE }}:buildcache
+          cache-to: type=registry,ref=${{ env.IMAGE }}:buildcache,mode=max
+
+      - name: Wait for Harbor policy, then add SHA tag
+        env:
+          PRIMARY: ${{ steps.tags.outputs.primary }}
+          QUALIFIED: ${{ steps.tags.outputs.qualified }}
+        run: |
+          for attempt in $(seq 1 60); do
+            if docker buildx imagetools inspect "$PRIMARY" >/dev/null 2>&1; then
+              docker buildx imagetools create --tag "$QUALIFIED" "$PRIMARY"
+              exit 0
+            fi
+            echo "waiting for Harbor scan/pull policy ($attempt/60)"
+            sleep 10
+          done
+          echo "Harbor did not approve $PRIMARY within 10 minutes" >&2
+          exit 1
+
+      - name: Summary
+        run: echo "pushed ${{ steps.tags.outputs.primary }} and ${{ steps.tags.outputs.qualified }}"
diff --git a/Dockerfile b/Dockerfile
index 5cb9e66..ca8c42d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM node:22-alpine AS css
+FROM harbor.pmagnus.cloud/dockerhub-cache/library/node:22-alpine AS css
 
 WORKDIR /build
 COPY package.json package-lock.json ./
@@ -8,7 +8,7 @@ COPY app/ app/
 COPY tailwind.config.js ./
 RUN npm run css:build
 
-FROM python:3.13-slim
+FROM harbor.pmagnus.cloud/dockerhub-cache/library/python:3.13-slim
 
 WORKDIR /app
 COPY requirements.txt .