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Use App Check with the debug provider on Android

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.

Use the debug provider in an emulator

To use the debug provider while running your app in an emulator interactively (during development, for example), do the following:

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 to control library versioning.
```
dependencies {
    // Import the BoM for the Firebase platform
    implementation(platform("com.google.firebase:firebase-bom:33.6.0"))

    // 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-debug")
}
```
By using the Firebase Android 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.
```
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-debug:18.0.0")
}
```
Looking for a Kotlin-specific library module? Starting in October 2023 (Firebase BoM 32.5.0), both Kotlin and Java developers can depend on the main library module (for details, see the FAQ about this initiative).

In your debug build, configure App Check to use the debug provider factory:

Kotlin+KTX

Firebase.initialize(context = this)
Firebase.appCheck.installAppCheckProviderFactory(
    DebugAppCheckProviderFactory.getInstance(),
)MainActivity.kt

Java

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

Launch the app and trigger a call to a Firebase backend service. A local debug token will be logged when the SDK tries to send a request to the backend. For example:
```
D DebugAppCheckProvider: Enter this debug secret into the allow list in
the Firebase Console for your project: 123a4567-b89c-12d3-e456-789012345678
```
In the App Check section of the Firebase console, choose Manage debug tokens from your app's overflow menu. Then, register the debug token you logged in the previous step.

After you register the token, Firebase backend services will accept it as valid.

Because this token allows access to your Firebase resources without a valid device, it is crucial that you keep it private. Don't commit it to a public repository, and if a registered token is ever compromised, revoke it immediately in the Firebase console.

Use the debug provider for unit testing in a CI environment

To use the debug provider for unit testing in a continuous integration (CI) environment, do the following:

In the App Check section of the Firebase console, choose Manage debug tokens from your app's overflow menu. Then, create a new debug token. You'll need the token in the next step.

Because this token allows access to your Firebase resources without a valid device, it is crucial that you keep it private. Don't commit it to a public repository, and if a registered token is ever compromised, revoke it immediately in the Firebase console.
Add the debug token you just created to your CI system's secure key store (for example, GitHub Actions' encrypted secrets or Travis CI's encrypted variables).
If necessary, configure your CI system to make your debug token available within the CI environment as an environment variable. Name the variable something like APP_CHECK_DEBUG_TOKEN_FROM_CI.
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 to control library versioning.
Kotlin+KTX
```
dependencies {
    // Import the BoM for the Firebase platform
    implementation(platform("com.google.firebase:firebase-bom:33.6.0"))

    // Add the dependency for the App Check library
    // When using the BoM, you don't specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-appcheck-debug")
}
```
By using the Firebase Android 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.
```
dependencies {
    // Add the dependency for the App Check library
    // When NOT using the BoM, you must specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-appcheck-debug:18.0.0")
}
```
Looking for a Kotlin-specific library module? Starting in October 2023 (Firebase BoM 32.5.0), both Kotlin and Java developers can depend on the main library module (for details, see the FAQ about this initiative).
Java
```
dependencies {
    // Import the BoM for the Firebase platform
    implementation(platform("com.google.firebase:firebase-bom:33.6.0"))

    // Add the dependency for the App Check library
    // When using the BoM, you don't specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-appcheck-debug")
}
```
By using the Firebase Android 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.
```
dependencies {
    // Add the dependency for the App Check library
    // When NOT using the BoM, you must specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-appcheck-debug:18.0.0")
}
```
Looking for a Kotlin-specific library module? Starting in October 2023 (Firebase BoM 32.5.0), both Kotlin and Java developers can depend on the main library module (for details, see the FAQ about this initiative).

Add the following to the configuration of your CI build variant:

testInstrumentationRunnerArguments["firebaseAppCheckDebugSecret"] =
    System.getenv("APP_CHECK_DEBUG_TOKEN_FROM_CI") ?: ""

In your test classes, use the DebugAppCheckTestHelper to wrap any code that needs an App Check token:

Kotlin+KTX

@RunWith(AndroidJunit4::class)
class MyTests {
    private val debugAppCheckTestHelper =
        DebugAppCheckTestHelper.fromInstrumentationArgs()

    @Test
    fun testWithDefaultApp() {
        debugAppCheckTestHelper.withDebugProvider {
            // Test code that requires a debug AppCheckToken.
        }
    }

    @Test
    fun testWithNonDefaultApp() {
        debugAppCheckTestHelper.withDebugProvider(
            FirebaseApp.getInstance("nonDefaultApp")
        ) {
            // Test code that requires a debug AppCheckToken.
        }
    }
}

Java

@RunWith(AndroidJunit4.class)
public class YourTests {
    private final DebugAppCheckTestHelper debugAppCheckTestHelper =
            DebugAppCheckTestHelper.fromInstrumentationArgs();

    @Test
    public void testWithDefaultApp() {
        debugAppCheckTestHelper.withDebugProvider(() -> {
            // Test code that requires a debug AppCheckToken.
        });
    }

    @Test
    public void testWithNonDefaultApp() {
        debugAppCheckTestHelper.withDebugProvider(
                FirebaseApp.getInstance("nonDefaultApp"),
                () -> {
                    // Test code that requires a debug AppCheckToken.
                });
    }
}

When your app runs in a CI environment, Firebase backend services will accept the token it sends as valid.