diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..82a07e7
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,80 @@
+name: CI
+
+on:
+  push:
+    branches: [main, dev, master]
+  pull_request:
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  backend:
+    name: Backend — lint / typecheck / test
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: backend
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+          cache-dependency-path: backend/package-lock.json
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Lint
+        run: npm run lint
+
+      - name: Type-check
+        run: npm run typecheck
+
+      - name: Run tests
+        run: npm test
+        env:
+          NODE_ENV: test
+          PUBLIC_APP_URL: http://localhost:5173
+          FRONTEND_URL: http://localhost:5173
+          ADMIN_API_KEY: ci-test-admin-key
+          GDRIVE_CLIENT_ID: placeholder
+          GDRIVE_CLIENT_SECRET: placeholder
+          GDRIVE_REFRESH_TOKEN: placeholder
+
+      - name: Build
+        run: npm run build
+
+  frontend:
+    name: Frontend — lint / test / build
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: cshare-app
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+          cache-dependency-path: cshare-app/package-lock.json
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Lint
+        run: npm run lint
+
+      - name: Run tests
+        run: npm test
+
+      - name: Build
+        run: npm run build
+        env:
+          VITE_API_BASE_URL: https://file.asabbagh.com