This page shows you how to enable App Check in an Android app, using the
built-in SafetyNet provider. When you enable App Check, you help ensure that
only your app can access your project's Firebase resources. See an
Overview
of this feature.
If you want to use App Check with your own custom provider, see
Implement a custom App Check provider
.
1. Set up your Firebase project
Add Firebase to your Android project
if you haven’t
already done so.
Register your apps to use App Check with the SafetyNet provider in the
App Check
section of the
Firebase console. You will need to
provide the SHA-256 fingerprint
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.
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
.
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.
2. Add the App Check library to your app
In your module (app-level) Gradle file (usually
app/build.gradle
), declare the
dependency for the App Check library for Android:
dependencies {
implementation 'com.google.firebase:firebase-appcheck-safetynet:16.1.2'
}
3. Initialize App Check
Add the following initialization code to your app so that it runs before you use
any other Firebase SDKs:
Kotlin+KTX
Firebase.initialize(context = this)
Firebase.appCheck.installAppCheckProviderFactory(
SafetyNetAppCheckProviderFactory.getInstance()
)
Java
FirebaseApp.initializeApp(/*context=*/ this);
FirebaseAppCheck firebaseAppCheck = FirebaseAppCheck.getInstance();
firebaseAppCheck.installAppCheckProviderFactory(
SafetyNetAppCheckProviderFactory.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:
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:
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
.