You can use Firebase Authentication to create and use temporary anonymous accounts to authenticate with Firebase. These temporary anonymous accounts can be used to allow users who haven't yet signed up to your app to work with data protected by security rules. If an anonymous user decides to sign up to your app, you can link their sign-in credentials to the anonymous account so that they can continue to work with their protected data in future sessions.
Before you begin
-
Use Swift Package Manager to install and manage Firebase dependencies.
- In Xcode, with your app project open, navigate to File > Add Packages.
- When prompted, add the Firebase Apple platforms SDK repository:
- Choose the Firebase Authentication library.
- Add the
-ObjC
flag to the Other Linker Flags section of your target's build settings. - When finished, Xcode will automatically begin resolving and downloading your dependencies in the background.
https://github.com/firebase/firebase-ios-sdk.git
- If you haven't yet connected your app to your Firebase project, do so from the Firebase console.
- Enable anonymous auth:
- In the Firebase console, open the Auth section.
- On the Sign-in Methods page, enable the Anonymous sign-in method.
- Optional: If you've upgraded your project to Firebase Authentication with Identity Platform, you can enable automatic clean-up. When you enable this setting, anonymous accounts older than 30 days will be automatically deleted. In projects with automatic clean-up enabled, anonymous authentication will no longer count toward usage limits or billing quotas. See Automatic clean-up.
Authenticate with Firebase anonymously
When a signed-out user uses an app feature that requires authentication with Firebase, sign in the user anonymously by completing the following steps:
- Import the
FirebaseCore
module in yourUIApplicationDelegate
, as well as any other Firebase modules your app delegate uses. For example, to use Cloud Firestore and Authentication:SwiftUI
import SwiftUI import FirebaseCore import FirebaseFirestore import FirebaseAuth // ...
Swift
import FirebaseCore import FirebaseFirestore import FirebaseAuth // ...
Objective-C
@import FirebaseCore; @import FirebaseFirestore; @import FirebaseAuth; // ...
- Configure a
FirebaseApp
shared instance in your app delegate'sapplication(_:didFinishLaunchingWithOptions:)
method:SwiftUI
// Use Firebase library to configure APIs FirebaseApp.configure()
Swift
// Use Firebase library to configure APIs FirebaseApp.configure()
Objective-C
// Use Firebase library to configure APIs [FIRApp configure];
- If you're using SwiftUI, you must create an application delegate and attach it
to your
App
struct viaUIApplicationDelegateAdaptor
orNSApplicationDelegateAdaptor
. You must also disable app delegate swizzling. For more information, see the SwiftUI instructions.SwiftUI
@main struct YourApp: App { // register app delegate for Firebase setup @UIApplicationDelegateAdaptor(AppDelegate.self) var delegate var body: some Scene { WindowGroup { NavigationView { ContentView() } } } }
- Call the
signInAnonymouslyWithCompletion:
method:Swift
Auth.auth().signInAnonymously { authResult, error in // ... }
Objective-C
[[FIRAuth auth] signInAnonymouslyWithCompletion:^(FIRAuthDataResult * _Nullable authResult, NSError * _Nullable error) { // ... }];
- If the
signInAnonymouslyWithCompletion:
method completes without error, you can get the anonymous user's account data from theFIRAuthDataResult
object:Swift
guard let user = authResult?.user else { return } let isAnonymous = user.isAnonymous // true let uid = user.uid
Objective-C
FIRUser *user = authResult.user; BOOL isAnonymous = user.anonymous; // YES NSString *uid = user.uid;
Convert an anonymous account to a permanent account
When an anonymous user signs up to your app, you might want to allow them to continue their work with their new account—for example, you might want to make the items the user added to their shopping cart before they signed up available in their new account's shopping cart. To do so, complete the following steps:
- When the user signs up, complete the sign-in flow for the user's
authentication provider up to, but not including, calling one of the
FIRAuth.signInWith
methods. For example, get the user's Google ID token, Facebook access token, or email address and password. Get an
FIRAuthCredential
for the new authentication provider:Google Sign-In
Swift
guard let authentication = user?.authentication, let idToken = authentication.idToken else { return } let credential = GoogleAuthProvider.credential(withIDToken: idToken, accessToken: authentication.accessToken)
Objective-C
FIRAuthCredential *credential = [FIRGoogleAuthProvider credentialWithIDToken:result.user.idToken.tokenString accessToken:result.user.accessToken.tokenString];
Facebook Login
Swift
let credential = FacebookAuthProvider .credential(withAccessToken: AccessToken.current!.tokenString)
Objective-C
FIRAuthCredential *credential = [FIRFacebookAuthProvider credentialWithAccessToken:[FBSDKAccessToken currentAccessToken].tokenString];
Email-password sign-in
Swift
let credential = EmailAuthProvider.credential(withEmail: email, password: password)
Objective-C
FIRAuthCredential *credential = [FIREmailAuthProvider credentialWithEmail:email password:password];
Pass the
FIRAuthCredential
object to the sign-in user'slinkWithCredential:completion:
method:Swift
user.link(with: credential) { authResult, error in // ... } }
Objective-C
[[FIRAuth auth].currentUser linkWithCredential:credential completion:^(FIRAuthDataResult *result, NSError *_Nullable error) { // ... }];
If the call to linkWithCredential:completion:
succeeds, the user's new account can
access the anonymous account's Firebase data.
Automatic clean-up
If you've upgraded your project to Firebase Authentication with Identity Platform, you can enable automatic clean-up in the Firebase console. When you enable this feature you allow Firebase to automatically delete anonymous accounts older than 30 days. In projects with automatic clean-up enabled, anonymous authentication will not count toward usage limits or billing quotas.
- Any anonymous accounts created after enabling automatic clean-up might be automatically deleted any time after 30 days post-creation.
- Existing anonymous accounts will be eligible for automatic deletion 30 days after enabling automatic clean-up.
- If you turn automatic clean-up off, any anonymous accounts scheduled to be deleted will remain scheduled to be deleted.
- If you "upgrade" an anonymous account by linking it to any sign-in method, the account will not get automatically deleted.
If you want to see how many users will be affected before you enable this feature, and you've
upgraded your project to Firebase Authentication with Identity Platform, you can filter by
is_anon
in Cloud
Logging.
Next steps
Now that users can authenticate with Firebase, you can control their access to data in your Firebase database using Firebase rules.