diff --git a/.github/workflows/autofix.yml b/.github/workflows/autofix.yml
new file mode 100644
index 00000000..171da622
--- /dev/null
+++ b/.github/workflows/autofix.yml
@@ -0,0 +1,27 @@
+name: autofix.ci # needed to securely identify the workflow
+
+on:
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  format:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Use Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20.x'
+          cache: 'yarn'
+
+      - name: Install dependencies
+        run: yarn install --immutable --immutable-cache --check-cache
+
+      - name: Format
+        run: yarn format
+
+      # See https://autofix.ci/
+      - uses: autofix-ci/action@635ffb0c9798bd160680f18fd73371e355b85f27
diff --git a/.prettierignore b/.prettierignore
new file mode 100644
index 00000000..1dcd66b2
--- /dev/null
+++ b/.prettierignore
@@ -0,0 +1,2 @@
+__fixtures__/
+__output__/