diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..0536ed4
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,75 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  contracts:
+    name: Contract Tests (Rust)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust stable
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: wasm32-unknown-unknown
+
+      - name: Cache Rust dependencies
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/bin/
+            ~/.cargo/registry/index/
+            ~/.cargo/registry/cache/
+            ~/.cargo/git/db/
+            target/
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: ${{ runner.os }}-cargo-
+
+      - name: Run contract tests
+        run: cargo test --workspace
+        working-directory: contracts
+
+  frontend:
+    name: Frontend Checks (TypeScript / pnpm)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 9
+
+      - name: Get pnpm store directory
+        id: pnpm-cache
+        shell: bash
+        run: echo "STORE_PATH=$(pnpm store path --silent)" >> $GITHUB_OUTPUT
+
+      - name: Cache pnpm dependencies
+        uses: actions/cache@v4
+        with:
+          path: ${{ steps.pnpm-cache.outputs.STORE_PATH }}
+          key: ${{ runner.os }}-pnpm-${{ hashFiles('**/pnpm-lock.yaml') }}
+          restore-keys: ${{ runner.os }}-pnpm-
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Type-check all packages
+        run: pnpm -r typecheck
+
+      - name: Lint frontend
+        run: pnpm --filter frontend lint
+
+      - name: Build frontend
+        run: pnpm --filter frontend build