Flutter: linkIdentityWithIdToken

Links an identity to an existing user using an ID token obtained from a third-party OAuth provider. This allows linking identities using native OAuth flows (Google, Apple, Facebook, etc.) similar to signInWithIdToken() but for linking rather than signing in.

• The Enable Manual Linking option must be enabled from your project's authentication settings.
• The user needs to be signed in to call linkIdentityWithIdToken().
• Supports the same OAuth providers as signInWithIdToken(): Google, Apple, Facebook, Kakao, and Keycloak.
• If the candidate identity is already linked to another user, the operation will fail.

Parameters

• provider

  (Required)

  The OAuth provider to link the identity from.

• idToken

  (Required)

  The identity token obtained from the third-party provider.

• accessToken

  (Optional)

  Access token obtained from the third-party provider. Required for Google sign in.

• nonce

  (Optional)

  Raw nonce value used to perform the third-party sign in. Required for Apple sign-in.

• captchaToken

  (Optional)

  The captcha token to be used for captcha verification.

Examples

Link Google identity

import 'package:google_sign_in/google_sign_in.dart';
import 'package:supabase_flutter/supabase_flutter.dart';

const webClientId = '<web client ID>';
const iosClientId = '<iOS client ID>';

final GoogleSignIn googleSignIn = GoogleSignIn(
  clientId: iosClientId,
  serverClientId: webClientId,
);
final googleUser = await googleSignIn.signIn();
final googleAuth = await googleUser!.authentication;
final accessToken = googleAuth.accessToken;
final idToken = googleAuth.idToken;

if (accessToken == null) {
  throw 'No Access Token found.';
}
if (idToken == null) {
  throw 'No ID Token found.';
}

final response = await supabase.auth.linkIdentityWithIdToken(
  provider: OAuthProvider.google,
  idToken: idToken,
  accessToken: accessToken,
);

Link Apple identity

import 'package:sign_in_with_apple/sign_in_with_apple.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:crypto/crypto.dart';

final rawNonce = supabase.auth.generateRawNonce();
final hashedNonce = sha256.convert(utf8.encode(rawNonce)).toString();

final credential = await SignInWithApple.getAppleIDCredential(
  scopes: [
    AppleIDAuthorizationScopes.email,
    AppleIDAuthorizationScopes.fullName,
  ],
  nonce: hashedNonce,
);

final idToken = credential.identityToken;
if (idToken == null) {
  throw const AuthException(
    'Could not find ID Token from generated credential.',
  );
}

final response = await supabase.auth.linkIdentityWithIdToken(
  provider: OAuthProvider.apple,
  idToken: idToken,
  nonce: rawNonce,
);