Plugin.Firebase.Auth 5.0.1

Auth

You can use Firebase Authentication to allow users to sign in to your app using one or more sign-in methods, including email address and password sign-in, and federated identity providers such as Google Sign-in and Facebook Login.

Installation

Nuget

Install-Package Plugin.Firebase.Auth

Setup

• Follow the instructions for the basic setup
• Enable Authentication at your project in the Firebase Console.
• When using Plugin.Firebase.Auth.Google, add the following lines of code after calling CrossFirebase.Initialize():

#if IOS
  FirebaseAuthGoogleImplementation.Initialize();
#elif ANDROID
  FirebaseAuthGoogleImplementation.Initialize("your-google-request-id-token");
#endif

• The googleRequestIdToken can be accessed at the Google API Console (make sure to use the Client-ID of the Web client)

iOS specifics

• Enable keychain entitlement in Entitlements.plist:

  <dict>
    <key>keychain-access-groups</key>
    <array>
      <string>$(AppIdentifierPrefix)my.fancy.app</string>
    </array>
  </dict>

• In case you are using Authentication via Google, add an url scheme to your apps Info.plist:

  <key>CFBundleURLTypes</key>
  <array>
    <dict>
      <key>CFBundleURLSchemes</key>
      <array>
        <string>com.googleusercontent.apps.123456-abcdef</string>
      </array>
    </dict>
  </array>

• For more specific instructions take a look at the official Firebase documentation

Android specifics

• Make sure you have added the SHA-1 fingerprint matching the keystore you've used for signing the app bundle to the android project settings in the firebase console:

• Call FirebaseAuthImplementation.HandleActivityResultAsync(requestCode, resultCode, data); from MainActivity.OnActivityResult(...)
• If you are on version 2.0.5 or later, add the following package to your project's .csproj file to prevent build errors:

  <PackageReference Include="Xamarin.AndroidX.Browser" Version="1.6.0.2" />

For more specific instructions take a look at the official Firebase documentation

Usage

Take a look at the documentation for the AdamE.Firebase.iOS.Auth packages, because Plugin.Firebase's code is abstracted but still very similar.

Since code should be documenting itself you can also take a look at the following classes:

• src/.../IFirebaseAuth.cs
• src/.../IFirebaseUser.cs
• tests/.../AuthFixture.cs
• sample/.../AuthService.cs

Language

Set LanguageCode = "fr" (or any BCP-47 code) before invoking an Auth flow that triggers user-facing content such as password-reset emails, email-verification emails, or phone-auth SMS. Call UseAppLanguage() to reset to the app language.

Error handling

Native Firebase Auth failures are wrapped in CrossPlatformFirebaseAuthException. The wrapper preserves the original native exception in InnerException and exposes stable inspection fields for the native exception type, domain, code, and message.

FirebaseAuthErrorClassifier.TryClassify(...) is an optional, best-effort helper for common failures such as invalid credentials, missing users, user collisions, weak passwords, recent-login requirements, and throttling. Call it explicitly in your app code when you want a simple cross-platform branch. When classification returns null, fall back to NativeExceptionTypeName, NativeErrorDomain, NativeErrorCode, NativeErrorMessage, or InnerException.

public async Task<string?> SignInAsync(string email, string password)
{
    try {
        await CrossFirebaseAuth.Current.SignInWithEmailAndPasswordAsync(email, password);
        return null;
    } catch(CrossPlatformFirebaseAuthException ex) {
        return FirebaseAuthErrorClassifier.TryClassify(ex) switch {
            FirebaseAuthFailure.InvalidCredentials => "Invalid email or password.",
            FirebaseAuthFailure.UserNotFound => "No account exists for that email address.",
            FirebaseAuthFailure.TooManyRequests => "Too many attempts. Try again later.",
            _ => ex.NativeErrorMessage
        };
    }
}

Migration from v4

Before v5, Auth failures were typically handled by catching FirebaseAuthException and inspecting its normalized Reason value.

In v5:

• Catch CrossPlatformFirebaseAuthException.
• Call FirebaseAuthErrorClassifier.TryClassify(ex) only if you want a simple cross-platform classification.
• Inspect NativeExceptionTypeName, NativeErrorDomain, NativeErrorCode, NativeErrorMessage, or InnerException when you need precise native details.
• SignOutAsync() now follows the same unified exception model when the underlying native Auth SDK reports a failure.

Release notes

• Version 5.0.0
  • Replace the normalized FirebaseAuthException / FIRAuthError model with CrossPlatformFirebaseAuthException.
  • Preserve native Firebase Auth exceptions in InnerException and expose platform-specific metadata for inspection.
  • Add FirebaseAuthErrorClassifier for best-effort, non-exhaustive classification of common Auth failures.
  • Migrate by catching CrossPlatformFirebaseAuthException, optionally calling FirebaseAuthErrorClassifier.TryClassify(ex), and using native metadata for precise handling.
• Version 4.0.1
  • Add ReloadCurrentUserAsync() to refresh the currently signed in user from the backend.
  • Add LanguageCode and UseAppLanguage() to control the language used for Auth-generated user-facing flows (reset/verification emails, SMS).
• Version 4.0.0
  • Upgrade baseline to .NET 9+.
  • Remove MAUI-specific dependencies (Auth remains usable from non-MAUI mobile .NET projects).
    • Android initialization now requires an ActivityLocator function (e.g. () => Platform.CurrentActivity).
  • Raise minimum platform versions (iOS 15+, Android 23+).
  • Raise minimum Firebase SDK versions (iOS 12.5+, Android BoM 33.0+).
  • Remove built-in Auth provider implementations (Facebook/Google/Apple); providers must be implemented directly via native SDKs per platform.
• Version 3.1.2
  • Fix NRE with Google Auth when cancelling sign in (#500)
• Version 3.1.1
  • Using AdamE.Firebase.iOS.* minimum version 11
• Version 3.1.0
  • Update to .net8
• Version 3.0.0
  • Swapped Xamarin.Firebase.iOS.Auth (native SDK 8.10.0) for AdamE.Firebase.iOS.Auth (native SDK 10.24.0)
• Version 2.0.7
  • Added AddAuthStateListener to FirebaseAuth (PR #246)
• Version 2.0.6
  • Fix dates in android AuthTokenResultWrapper (issue #244)
• Version 2.0.5
  • Bump up Xamarin.Firebase.Auth from 121.0.8 to 122.2.0 (issue #131)
• Version 2.0.4
  • Separating Auth.Google into its own package (PR #210)
• Version 2.0.3
  • Return FirebaseUser in FirebaseAuthImplementation.CreateUserAsync(email, password) method (issue #183)
• Version 2.0.2
  • Bump up Xamarin.Google.iOS.SignIn from 5.0.2.3 to 5.0.2.4 (issue #158)
• Version 2.0.1
  • Remove unnecessary UseMaui property from csproj files
  • Readd net6.0 tfm