diff --git a/.github/workflows/format-prettier.yml b/.github/workflows/format-prettier.yml
new file mode 100644
index 000000000..5b33ebdf1
--- /dev/null
+++ b/.github/workflows/format-prettier.yml
@@ -0,0 +1,34 @@
+name: Format with Prettier
+
+on:
+  workflow_dispatch:
+  pull_request:
+    types: [opened, synchronize]
+
+jobs:
+  prettier:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout (full)
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Use Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '18'
+
+      - name: Install dependencies
+        run: |
+          npm ci || npm install
+          npm install --no-save prettier
+
+      - name: Run Prettier (format)
+        run: npx prettier --write "**/*.{js,jsx,ts,tsx,json,md}"
+
+      - name: Commit formatted changes
+        uses: EndBug/add-and-commit@v9
+        with:
+          message: "chore: format code with Prettier"
+          add: "."