diff --git a/.github/workflows/docker-publish.yml b/.github/workflows/docker-publish.yml
index e797abd..4833a39 100644
--- a/.github/workflows/docker-publish.yml
+++ b/.github/workflows/docker-publish.yml
@@ -13,13 +13,22 @@ env:
   IMAGE_NAME: ${{ github.repository }}
 
 jobs:
-  build-and-push-frontend:
-    runs-on: ubuntu-latest
+  build-frontend:
+    runs-on: ${{ matrix.runner }}
     permissions:
       contents: read
       packages: write
       id-token: write
 
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - platform: linux/amd64
+            runner: ubuntu-latest
+          - platform: linux/arm64
+            runner: ubuntu-24.04-arm
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -35,6 +44,66 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v5.0.0
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}-frontend
+
+      - name: Build and push Docker image by digest
+        id: build
+        uses: docker/build-push-action@v5.0.0
+        with:
+          context: ./frontend
+          platforms: ${{ matrix.platform }}
+          push: ${{ github.event_name != 'pull_request' }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha,scope=frontend-${{ matrix.platform }}
+          cache-to: type=gha,mode=max,scope=frontend-${{ matrix.platform }}
+          outputs: type=image,name=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}-frontend,push-by-digest=true,name-canonical=true,push=${{ github.event_name != 'pull_request' }}
+
+      - name: Export digest
+        if: github.event_name != 'pull_request'
+        run: |
+          mkdir -p /tmp/digests/frontend
+          digest="${{ steps.build.outputs.digest }}"
+          touch "/tmp/digests/frontend/${digest#sha256:}"
+
+      - name: Upload digest
+        if: github.event_name != 'pull_request'
+        uses: actions/upload-artifact@v4
+        with:
+          name: digests-frontend-${{ matrix.platform == 'linux/amd64' && 'amd64' || 'arm64' }}
+          path: /tmp/digests/frontend/*
+          if-no-files-found: error
+          retention-days: 1
+
+  merge-frontend:
+    runs-on: ubuntu-latest
+    if: github.event_name != 'pull_request'
+    needs: build-frontend
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Download digests
+        uses: actions/download-artifact@v4
+        with:
+          path: /tmp/digests/frontend
+          pattern: digests-frontend-*
+          merge-multiple: true
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3.0.0
+
+      - name: Log into registry ${{ env.REGISTRY }}
+        uses: docker/login-action@v3.0.0
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
       - name: Extract Docker metadata
         id: meta
         uses: docker/metadata-action@v5.0.0
@@ -45,25 +114,29 @@ jobs:
             type=semver,pattern={{major}}.{{minor}}
             type=raw,value=latest,enable={{is_default_branch}}
 
-      - name: Build and push Docker image
-        id: build-and-push
-        uses: docker/build-push-action@v5.0.0
-        with:
-          context: ./frontend
-          platforms: linux/amd64,linux/arm64
-          push: ${{ github.event_name != 'pull_request' }}
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+      - name: Create and push manifest
+        working-directory: /tmp/digests/frontend
+        run: |
+          docker buildx imagetools create \
+            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf '${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}-frontend@sha256:%s ' *)
 
-  build-and-push-backend:
-    runs-on: ubuntu-latest
+  build-backend:
+    runs-on: ${{ matrix.runner }}
     permissions:
       contents: read
       packages: write
       id-token: write
 
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - platform: linux/amd64
+            runner: ubuntu-latest
+          - platform: linux/arm64
+            runner: ubuntu-24.04-arm
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -79,6 +152,66 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v5.0.0
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}-backend
+
+      - name: Build and push Docker image by digest
+        id: build
+        uses: docker/build-push-action@v5.0.0
+        with:
+          context: ./backend
+          platforms: ${{ matrix.platform }}
+          push: ${{ github.event_name != 'pull_request' }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha,scope=backend-${{ matrix.platform }}
+          cache-to: type=gha,mode=max,scope=backend-${{ matrix.platform }}
+          outputs: type=image,name=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}-backend,push-by-digest=true,name-canonical=true,push=${{ github.event_name != 'pull_request' }}
+
+      - name: Export digest
+        if: github.event_name != 'pull_request'
+        run: |
+          mkdir -p /tmp/digests/backend
+          digest="${{ steps.build.outputs.digest }}"
+          touch "/tmp/digests/backend/${digest#sha256:}"
+
+      - name: Upload digest
+        if: github.event_name != 'pull_request'
+        uses: actions/upload-artifact@v4
+        with:
+          name: digests-backend-${{ matrix.platform == 'linux/amd64' && 'amd64' || 'arm64' }}
+          path: /tmp/digests/backend/*
+          if-no-files-found: error
+          retention-days: 1
+
+  merge-backend:
+    runs-on: ubuntu-latest
+    if: github.event_name != 'pull_request'
+    needs: build-backend
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Download digests
+        uses: actions/download-artifact@v4
+        with:
+          path: /tmp/digests/backend
+          pattern: digests-backend-*
+          merge-multiple: true
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3.0.0
+
+      - name: Log into registry ${{ env.REGISTRY }}
+        uses: docker/login-action@v3.0.0
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
       - name: Extract Docker metadata
         id: meta
         uses: docker/metadata-action@v5.0.0
@@ -89,14 +222,9 @@ jobs:
             type=semver,pattern={{major}}.{{minor}}
             type=raw,value=latest,enable={{is_default_branch}}
 
-      - name: Build and push Docker image
-        id: build-and-push
-        uses: docker/build-push-action@v5.0.0
-        with:
-          context: ./backend
-          platforms: linux/amd64,linux/arm64
-          push: ${{ github.event_name != 'pull_request' }}
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+      - name: Create and push manifest
+        working-directory: /tmp/digests/backend
+        run: |
+          docker buildx imagetools create \
+            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf '${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}-backend@sha256:%s ' *)
diff --git a/.gitignore b/.gitignore
index ca4993a..87dc843 100644
--- a/.gitignore
+++ b/.gitignore
@@ -94,3 +94,6 @@ clean_zip.py
 zip_repo.py
 refactor_cesium.py
 jobs.json
+
+.claude
+.mise.local.toml
diff --git a/backend/Dockerfile b/backend/Dockerfile
index 225f635..8616154 100644
--- a/backend/Dockerfile
+++ b/backend/Dockerfile
@@ -9,16 +9,18 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     && apt-get install -y --no-install-recommends nodejs \
     && rm -rf /var/lib/apt/lists/*
 
-# Install dependencies
+# Install Python dependencies
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
+# Install Node.js dependencies (ws module for AIS WebSocket proxy)
+# Copy manifests first so this layer is cached unless deps change
+COPY package*.json ./
+RUN npm install --omit=dev
+
 # Copy source code
 COPY . .
 
-# Install Node.js dependencies (ws module for AIS WebSocket proxy)
-RUN npm install --omit=dev
-
 # Create a non-root user for security
 RUN adduser --system --uid 1001 backenduser \
     && chown -R backenduser /app