diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..a47bc65
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,42 @@
+name: CI — Lint, Test, Smoke
+
+on:
+  pull_request:
+    branches: [master]
+  push:
+    branches: [master]
+
+jobs:
+  quality:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version-file: '.nvmrc'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Lint (ESLint)
+        run: npm run lint
+
+      - name: Lint (Markdown)
+        run: npm run lint:md
+
+      - name: Format check (Prettier)
+        run: npm run format:check
+
+      - name: Run tests
+        run: npm test
+
+      - name: Smoke test
+        run: npm run smoke
+
+      - name: API validation tests
+        run: npm run test:validation