diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..c917d68
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,52 @@
+name: CI
+
+on:
+  pull_request:
+
+permissions:
+  contents: read
+  pull-requests: write
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+          cache: gradle
+
+      - name: Grant execute permission for gradlew
+        run: chmod +x gradlew
+
+      - name: Run unit tests
+        run: ./gradlew test
+
+      - name: Build debug APK
+        run: ./gradlew assembleDebug
+
+      - name: Upload APK
+        id: upload-apk
+        uses: actions/upload-artifact@v4
+        with:
+          name: app-debug
+          path: app/build/outputs/apk/debug/app-debug.apk
+          if-no-files-found: error
+          retention-days: 7
+
+      - name: Comment APK download link on PR
+        uses: actions/github-script@v7
+        with:
+          script: |
+            await github.rest.issues.createComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.issue.number,
+              body: `### 📦 Debug APK ready\n\n[Download app-debug.apk](${{ steps.upload-apk.outputs.artifact-url }})`
+            })