Manage Users in Firebase

Create a user

You create a new user in your Firebase project in four ways:

  • Call the createUserWithEmailAndPassword() method.
  • Sign in a user for the first time using a federated identity provider, such as Google Sign-In, Facebook Login, or Apple.

You can also create new password-authenticated users from the Authentication section of the Firebase console, on the Users page.

Get a user's profile

To get a user's profile information, use the properties of User. There are three ways to get a User object representing the current user:

  • The authStateChanges, idTokenChanges and userChanges streams: your listeners will receive the current User, or null if no user is authenticated:

    FirebaseAuth.instance
  .authStateChanges()
  .listen((User? user) {
    if (user != null) {
      print(user.uid);
    }
  });

    When the app starts, an event fires after the user credentials (if any) from local storage have been restored, meaning that your listeners always get called when the user state is initialized. Then, whenever the authentication state changes, a new event will be raised with the updated user state.

    By listening to the authentication state, you can build a user interface that reacts to these changes in authentication state.

  • The UserCredential object returned by the authentication (signIn-) methods: the UserCredential object has a user property with the current User:

    final userCredential =
    await FirebaseAuth.instance.signInWithCredential(credential);
final user = userCredential.user;
print(user?.uid);

  • The currentUser property of the FirebaseAuth instance: if you are sure the user is currently signed-in, you can access the User from the currentUser property:

    if (FirebaseAuth.instance.currentUser != null) {
  print(FirebaseAuth.instance.currentUser?.uid);
}

    The currentUser can be null for two reasons:

    • The user isn't signed in.
    • The auth object has not finished initializing. If you use a listener to keep track of the user's sign-in status, you don't need to handle this case.

Get a user's provider-specific profile information

To get the profile information retrieved from the sign-in providers linked to a user, use the providerData property. For example:

if (user != null) {
    for (final providerProfile in user.providerData) {
        // ID of the provider (google.com, apple.com, etc.)
        final provider = providerProfile.providerId;

        // UID specific to the provider
        final uid = providerProfile.uid;

        // Name, email address, and profile photo URL
        final name = providerProfile.displayName;
        final emailAddress = providerProfile.email;
        final profilePhoto = providerProfile.photoURL;
    }
}

Update a user's profile

You can update a user's basic profile information—the user's display name and profile photo URL—with the update- methods. For example:

await user?.updateDisplayName("Jane Q. User");
await user?.updatePhotoURL("https://example.com/jane-q-user/profile.jpg");

Set a user's email address

You can set a user's email address with the updateEmail() method. For example:

await user?.updateEmail("[email protected]");

Send a user a verification email

You can send an address verification email to a user with the sendEmailVerification() method. For example:

await user?.sendEmailVerification();

You can customize the email template that is used in Authentication section of the Firebase console, on the Email Templates page. See Email Templates in Firebase Help Center.

It is also possible to pass state via a continue URL to redirect back to the app when sending a verification email.

Additionally you can localize the verification email by updating the language code on the Auth instance before sending the email. For example:

await FirebaseAuth.instance.setLanguageCode("fr");
await user?.sendEmailVerification();

Set a user's password

You can set a user's password with the updatePassword() method. For example:

await user?.updatePassword(newPassword);

Send a password reset email

You can send a password reset email to a user with the sendPasswordResetEmail() method. For example:

await FirebaseAuth.instance
    .sendPasswordResetEmail(email: "[email protected]");

You can customize the email template that is used in Authentication section of the Firebase console, on the Email Templates page. See Email Templates in Firebase Help Center.

It is also possible to pass state via a continue URL to redirect back to the app when sending a password reset email.

Additionally you can localize the password reset email by updating the language code on the Auth instance before sending the email. For example:

await FirebaseAuth.instance.setLanguageCode("fr");

You can also send password reset emails from the Firebase console.

Delete a user

You can delete a user account with the delete() method. For example:

await user?.delete();

You can also delete users from the Authentication section of the Firebase console, on the Users page.

Re-authenticate a user

Some security-sensitive actions—such as deleting an account, setting a primary email address, and changing a password—require that the user has recently signed in. If you perform one of these actions, and the user signed in too long ago, the action fails and throws a FirebaseAuthException with the code requires-recent-login. When this happens, re-authenticate the user by getting new sign-in credentials from the user and passing the credentials to reauthenticate. For example:

// Prompt the user to re-provide their sign-in credentials.
// Then, use the credentials to reauthenticate:
await user?.reauthenticateWithCredential(credential);

Import user accounts

You can import user accounts from a file into your Firebase project by using the Firebase CLI's auth:import command. For example:

firebase auth:import users.json --hash-algo=scrypt --rounds=8 --mem-cost=14