diff --git a/.gitea/workflows/docker-ext.yml b/.gitea/workflows/docker-ext.yml
new file mode 100644
index 0000000..b3f4f92
--- /dev/null
+++ b/.gitea/workflows/docker-ext.yml
@@ -0,0 +1,57 @@
+name: Build and Push Docker image (ext)
+
+on:
+  push:
+    branches:
+      - dev4
+
+env:
+  REGISTRY: git.4nkweb.com
+  IMAGE_NAMESPACE: 4nk
+  IMAGE_NAME: ihm_client
+  DOCKER_TAG: ext
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ secrets.REGISTRY_USERNAME }}
+          password: ${{ secrets.REGISTRY_PASSWORD }}
+
+      - name: Extract docker tag from commit message (optional)
+        id: tag
+        run: |
+          set -euo pipefail
+          MSG=$(git log -1 --pretty=%B | tr -d '\r')
+          if echo "$MSG" | grep -q "ci: docker_tag="; then
+            T=$(echo "$MSG" | sed -nE 's/.*ci: docker_tag=([^ ]+).*/\1/p' | tr -d '\n')
+            if [ -n "$T" ]; then
+              echo "tag=$T" >> $GITHUB_OUTPUT
+            fi
+          fi
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          platforms: linux/amd64
+          tags: |
+            ${{ env.REGISTRY }}/${{ env.IMAGE_NAMESPACE }}/${{ env.IMAGE_NAME }}:${{ steps.tag.outputs.tag || env.DOCKER_TAG }}
+          cache-from: type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_NAMESPACE }}/${{ env.IMAGE_NAME }}:buildcache
+          cache-to: type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_NAMESPACE }}/${{ env.IMAGE_NAME }}:buildcache,mode=max
+
+