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

App Check uses [App Attest](https://developer.apple.com/documentation/devicecheck/establishing_your_app_s_integrity)
to verify that requests to Firebase services are coming from your authentic app.
App Check currently does not use App Attest to
[analyze fraud risk](https://developer.apple.com/documentation/devicecheck/assessing_fraud_risk).

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/ios/custom-provider.md.txt).

> [!NOTE]
> **Note:** If you are adding App Attest to a production app with a large active user base, Apple recommends [gradually onboarding users](https://developer.apple.com/documentation/devicecheck/preparing-to-use-the-app-attest-service#Onboard-users-gradually) to avoid encountering quota limits.

## 1. Set up your Firebase project

1. You will need Xcode 12.5+ to use App Attest.

2. [Add Firebase to your Apple project](https://firebase.google.com/docs/ios/setup.md.txt) if you haven't already
   done so.

3. In the Firebase console, navigate to **Security** \>
   [**App Check**](https://console.firebase.google.com/project/_/appcheck/).

4. In the **Apps** tab, register your apps to use App Check with the
   App Attest provider.

   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.
5. <br />

   <br />

   **Optional**: Set the token time to live (TTL).

   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.md.txt#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 />

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

1. Use [Swift Package Manager](https://firebase.google.com/docs/ios/swift-package-manager) to install and
   manage Firebase dependencies.

   In Xcode, with your app project open, navigate to **File \> Add Packages** ,
   add the Firebase Apple platforms SDK repository
   (`https://github.com/firebase/firebase-ios-sdk`), and choose the
   **FirebaseAppCheck** library.

   > [!NOTE]
   > **Note:** If you've already added the Firebase Apple platforms SDK to your project, you can add **FirebaseAppCheck** to your app target using the **Frameworks, Libraries, and Embedded Content** section of your target's settings.

2. In Xcode, add the **App Attest** capability to your app.

3. In your project's `.entitlements` file, set the App Attest environment to
   `production`.

   > [!NOTE]
   > **Note:** App Check currently doesn't accept tokens generated in the App Attest sandbox environment.

## 3. Initialize App Check

You will need to initialize App Check before you use any other Firebase
SDKs.

First, write an implementation of `AppCheckProviderFactory`. The specifics of
your implementation will depend on your use case.

For example, If you only have users on iOS 14 and later, you can simply always
create `AppAttestProvider` objects:

### Swift


**Note:** This Firebase product is not available on watchOS targets.

```swift
class YourSimpleAppCheckProviderFactory: NSObject, AppCheckProviderFactory {
  func createProvider(with app: FirebaseApp) -> AppCheckProvider? {
    return AppAttestProvider(app: app)
  }
}
```

<br />

### Objective-C


**Note:** This Firebase product is not available on watchOS targets.

```objective-c
@interface YourSimpleAppCheckProviderFactory : NSObject <FIRAppCheckProviderFactory>
@end

@implementation YourSimpleAppCheckProviderFactory

- (nullable id<FIRAppCheckProvider>)createProviderWithApp:(nonnull FIRApp *)app {
  return [[FIRAppAttestProvider alloc] initWithApp:app];
}

@end
```

Or, you can create `AppAttestProvider` objects on iOS 14 and later, and fall
back to `DeviceCheckProvider` on earlier versions:

### Swift


**Note:** This Firebase product is not available on watchOS targets.

```swift
class YourAppCheckProviderFactory: NSObject, AppCheckProviderFactory {
  func createProvider(with app: FirebaseApp) -> AppCheckProvider? {
    if #available(iOS 14.0, *) {
      return AppAttestProvider(app: app)
    } else {
      return DeviceCheckProvider(app: app)
    }
  }
}
```

<br />

### Objective-C


**Note:** This Firebase product is not available on watchOS targets.

```objective-c
@interface YourAppCheckProviderFactory : NSObject <FIRAppCheckProviderFactory>
@end

@implementation YourAppCheckProviderFactory

- (nullable id<FIRAppCheckProvider>)createProviderWithApp:(nonnull FIRApp *)app {
  if (@available(iOS 14.0, *)) {
    return [[FIRAppAttestProvider alloc] initWithApp:app];
  } else {
    return [[FIRDeviceCheckProvider alloc] initWithApp:app];
  }
}

@end
```

<br />

After you have implemented a `AppCheckProviderFactory` class, configure
App Check to use it:

### Swift


**Note:** This Firebase product is not available on watchOS targets.

```swift
let providerFactory = YourAppCheckProviderFactory()
AppCheck.setAppCheckProviderFactory(providerFactory)

FirebaseApp.configure()
```

<br />

### Objective-C


**Note:** This Firebase product is not available on watchOS targets.

```objective-c
YourAppCheckProviderFactory *providerFactory =
        [[YourAppCheckProviderFactory alloc] init];
[FIRAppCheck setAppCheckProviderFactory:providerFactory];

[FIRApp configure];
```

<br />

## Next steps

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

> [!NOTE]
> **Note:** If you are adding App Attest to a production app with a large active user base, Apple recommends [gradually onboarding users](https://developer.apple.com/documentation/devicecheck/preparing-to-use-the-app-attest-service#Onboard-users-gradually) to avoid encountering quota limits.

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.md.txt) for Firebase AI Logic, SQL 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.md.txt).

### 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.md.txt) for Firebase AI Logic, SQL 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.md.txt).

### 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 a simulator 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 Apple platforms](https://firebase.google.com/docs/app-check/ios/debug-provider.md.txt).