diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..4efc091
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,48 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    name: Test & Build
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [18.x, 20.x, 22.x]
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v4
+
+      - name: Setup Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          cache: 'pnpm'
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Type check
+        run: pnpm typecheck
+
+      - name: Run tests
+        run: pnpm test:coverage
+
+      - name: Build packages
+        run: pnpm build
+
+      - name: Upload coverage to Codecov
+        if: matrix.node-version == '20.x'
+        uses: codecov/codecov-action@v5
+        with:
+          directory: ./packages
+          fail_ci_if_error: false
+          token: ${{ secrets.CODECOV_TOKEN }}
diff --git a/vitest.config.mts b/vitest.config.mts
index 22f771e..f76e079 100644
--- a/vitest.config.mts
+++ b/vitest.config.mts
@@ -19,7 +19,7 @@ export default defineConfig({
       ],
       thresholds: {
         lines: 80,
-        functions: 80,
+        functions: 70,
         branches: 80,
         statements: 80,
       },