<br />

This page shows you how to enable App Check in an Android app, using the
built-in Play Integrity provider. When you enable App Check, you help ensure
that only your app can access your project's backend resources. See an
[Overview](https://firebase.google.com/docs/app-check) of this feature.

The Play Integrity provider supports Android apps that are published on Google
Play, outside Google Play, or both. If your use case requires Play Integrity
features not implemented by App Check, or if you want to use App Check
with your own custom provider, see [Implement a custom App Check provider](https://firebase.google.com/docs/app-check/android/custom-provider).

## 1. Set up your Firebase project

1. [Add Firebase to your Android project](https://firebase.google.com/docs/android/setup) if you haven't
   already done so.

2. Enable the Play Integrity API:

   1. In the [Google Play Console](https://play.google.com/console/developers/),
      select your app, or add it if you haven't already done so.

   2. In the **Release** section, click **App integrity**.

   3. Go to the **Play Integrity API** section of the page, click **Link Cloud project**,
      then select your Firebase project from the list of Google Cloud projects.
      The project you select here must be the same Firebase project as the one
      in which you register your app (see the next step).

      <br />

      | You must be an **Owner** of the project you want to link. Note that being a member of a group that has been assigned the Owner role is insufficient.

      <br />

3. Register your apps to use App Check with the Play Integrity provider in
   the [**App Check**](https://console.firebase.google.com/project/_/appcheck) section of
   the Firebase console. You will need to [provide the SHA-256 fingerprint](https://developers.google.com/android/guides/client-auth)
   of your app's signing certificate.

   You usually need to register all of your project's apps, because once you
   enable enforcement for a Firebase product, only registered apps will be able
   to access the product's backend resources.
4. <br />

   <br />

   **Optional** : In the app registration settings, set a custom time-to-live
   (TTL) for App Check tokens issued by the provider. You can set the TTL
   to any value between 30 minutes and 7 days. When changing this value, be
   aware of the following tradeoffs:
   - Security: Shorter TTLs provide stronger security, because it reduces the window in which a leaked or intercepted token can be abused by an attacker.
   - Performance: Shorter TTLs mean your app will perform attestation more frequently. Because the app attestation process adds latency to network requests every time it's performed, a short TTL can impact the performance of your app.
   - Quota and cost: Shorter TTLs and frequent re-attestation deplete your quota faster, and for paid services, potentially cost more. See [Quotas \& limits](https://firebase.google.com/docs/app-check#quotas_limits).

   The default TTL of
   **1 hour**
   is reasonable for most apps. Note that the App Check library refreshes
   tokens at approximately half the TTL duration.

   <br />

   <br />

### Configure advanced settings (optional)

App Check offers a number of settings to support advanced use cases,
including distributing your app outside Google Play. You can configure these
settings in the [**App Check**](https://console.firebase.google.com/project/_/appcheck)
section of the Firebase console for each of your Android apps. We recommend
that you configure these settings according to the following table when you
first [register your app](https://firebase.google.com/docs/app-check/android/play-integrity-provider#project-setup).

| Your app's distribution channel | PLAY_RECOGNIZED | LICENSED | Minimum acceptable device integrity level |
|---|---|---|---|
| Exclusively on Google Play | Required | Required | Don't explicitly check device integrity level |
| Exclusively outside Google Play | Not required | Not required | Device integrity |
| On Google Play and outside Google Play | Required | Not required | Don't explicitly check device integrity level |

#### Details

Each advanced setting corresponds to a Play Integrity verdict label. Consult the
[Play Integrity documentation](https://developer.android.com/google/play/integrity/verdicts)
for additional details.

- By default, App Check requires the [`PLAY_RECOGNIZED`](https://developer.android.com/google/play/integrity/verdicts#application-integrity-field) app recognition label. Apps not published on Google Play are not eligible to receive this label.
- By default, App Check doesn't require the [`LICENSED`](https://developer.android.com/google/play/integrity/verdicts#account-details-field) app licensing label. Only users who have installed or updated your app directly from Google Play are eligible to receive this label.
- By default, App Check does not explicitly check the device integrity
  verdict. App Check supports explicitly checking for the following three
  device integrity levels, listed in order of increasing device integrity.

  | **Note:** Play Integrity may *implicitly* perform additional device integrity checks during the evaluation of other integrity verdicts; you cannot directly control these implicit checks, and they are **not** affected by this setting.
  - **Basic integrity** . Causes App Check to require the
    [`MEETS_BASIC_INTEGRITY`](https://developer.android.com/google/play/integrity/verdicts#optional-device-labels)
    device recognition label. In order for your app to be eligible to
    receive this *optional* label, you must first
    [opt in from the Google Play Console](https://developer.android.com/google/play/integrity/setup#optional).

    | **Warning:** Because your Android 13+ users who don't install or update your app from Google Play are ineligible to receive this label, they will be denied access if they are unable to meet the requirements for the stronger `MEETS_DEVICE_INTEGRITY` label. Consider using this setting only as a tool to relax device integrity requirements for users who install or update your app from Google Play. For more details, see the [Play Integrity documentation](https://developer.android.com/google/play/integrity/improvements).
  - **Device integrity** . Causes App Check to require the
    [`MEETS_DEVICE_INTEGRITY`](https://developer.android.com/google/play/integrity/verdicts#device-integrity-field)
    device recognition label. All apps are automatically eligible to
    receive this label.

  - **Strong integrity** . Causes App Check to require the
    [`MEETS_STRONG_INTEGRITY`](https://developer.android.com/google/play/integrity/verdicts#optional-device-labels)
    device recognition label. In order for your app to be eligible to
    receive this *optional* label, you must first
    [opt in from the Google Play Console](https://developer.android.com/google/play/integrity/setup#optional).

    | **Warning:** Because your Android 13+ users who don't install or update your app from Google Play are ineligible to receive this label, you should only consider using this setting if your app is distributed exclusively using Google Play. For more details, see the [Play Integrity documentation](https://developer.android.com/google/play/integrity/improvements).

## 2. Add the App Check library to your app

In your **module (app-level) Gradle file** (usually `<project>/<app-module>/build.gradle.kts` or `<project>/<app-module>/build.gradle`), add the dependency for the App Check library for Android. We recommend using the [Firebase Android BoM](https://firebase.google.com/docs/android/learn-more#bom) to control library versioning.

<br />

```carbon
dependencies {
    // Import the BoM for the Firebase platform
    implementation(platform("com.google.firebase:firebase-bom:34.8.0"))

    // Add the dependencies for the App Check libraries
    // When using the BoM, you don't specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-appcheck-playintegrity")
}
```

By using the [Firebase Android BoM](https://firebase.google.com/docs/android/learn-more#bom),
your app will always use compatible versions of Firebase Android libraries.
*(Alternative)*
Add Firebase library dependencies *without* using the BoM

If you choose not to use the Firebase BoM, you must specify each Firebase library version
in its dependency line.

**Note that if you use *multiple* Firebase libraries in your app, we strongly
recommend using the BoM to manage library versions, which ensures that all versions are
compatible.**  

```groovy
dependencies {
    // Add the dependencies for the App Check libraries
    // When NOT using the BoM, you must specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-appcheck-playintegrity:19.0.1")
}
```

<br />

## 3. Initialize App Check

Add the following initialization code to your app so that it runs before you use
any other Firebase SDKs:  

### Kotlin

```kotlin
Firebase.initialize(context = this)
Firebase.appCheck.installAppCheckProviderFactory(
    PlayIntegrityAppCheckProviderFactory.getInstance(),
)
```

### Java

```java
FirebaseApp.initializeApp(/*context=*/ this);
FirebaseAppCheck firebaseAppCheck = FirebaseAppCheck.getInstance();
firebaseAppCheck.installAppCheckProviderFactory(
        PlayIntegrityAppCheckProviderFactory.getInstance());
```

## Next steps

Once the App Check library is installed in your app, start distributing the
updated app to your users.

The updated client app will begin sending App Check tokens along with every
request it makes to Firebase, but Firebase products will not require the tokens
to be valid until you enable enforcement in the App Check section of the
Firebase console.

### Monitor metrics and enable enforcement

Before you enable enforcement, however, you should make sure that doing so won't
disrupt your existing legitimate users. On the other hand, if you're seeing
suspicious use of your app resources, you might want to enable enforcement
sooner.

To help make this decision, you can look at App Check metrics for the
services you use:

- [Monitor App Check request metrics](https://firebase.google.com/docs/app-check/monitor-metrics) for Firebase AI Logic, Data Connect, Realtime Database, Cloud Firestore, Cloud Storage, Authentication, Google Identity for iOS, Maps JavaScript API, and Places API (New).
- [Monitor App Check request metrics for Cloud Functions](https://firebase.google.com/docs/app-check/monitor-functions-metrics).

### Enable App Check enforcement

When you understand how App Check will affect your users and you're ready to
proceed, you can enable App Check enforcement:

- [Enable App Check enforcement](https://firebase.google.com/docs/app-check/enable-enforcement) for Firebase AI Logic, Data Connect, Realtime Database, Cloud Firestore, Cloud Storage, Authentication, Google Identity for iOS, Maps JavaScript API, and Places API (New).
- [Enable App Check enforcement for Cloud Functions](https://firebase.google.com/docs/app-check/cloud-functions).

### Use App Check in debug environments

If, after you have registered your app for App Check, you want to run your
app in an environment that App Check would normally not classify as valid,
such as an emulator during development, or from a continuous integration (CI)
environment, you can create a debug build of your app that uses the
App Check debug provider instead of a real attestation provider.

See [Use App Check with the debug provider on Android](https://firebase.google.com/docs/app-check/android/debug-provider).