Manage Users in Firebase

Create a user

You create a new user in your Firebase project by calling the createUserWithEmailAndPassword method or by signing in a user for the first time using a federated identity provider, such as Google Sign-In or Facebook Login.

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

Get the currently signed-in user

The recommended way to get the current user is by calling the getCurrentUser method. If no user is signed in, getCurrentUser returns null:

Kotlin

valuser=Firebase.auth.currentUserif(user!=null){// User is signed in}else{// No user is signed in}
MainActivity.kt

Java

FirebaseUseruser=FirebaseAuth.getInstance().getCurrentUser();if(user!=null){// User is signed in}else{// No user is signed in}
MainActivity.java

There are some cases where getCurrentUser will return a non-null FirebaseUser but the underlying token is not valid. This can happen, for example, if the user was deleted on another device and the local token has not refreshed. In this case, you may get a valid user getCurrentUser but subsequent calls to authenticated resources will fail.

getCurrentUser might also return null because the auth object has not finished initializing.

If you attach an AuthStateListener you will get a callback every time the underlying token state changes. This can be useful to react to edge cases like those mentioned above.

Get a user's profile

To get a user's profile information, use the accessor methods of an instance of FirebaseUser. For example:

Kotlin

valuser=Firebase.auth.currentUseruser?.let{// Name, email address, and profile photo Urlvalname=it.displayNamevalemail=it.emailvalphotoUrl=it.photoUrl// Check if user's email is verifiedvalemailVerified=it.isEmailVerified// The user's ID, unique to the Firebase project. Do NOT use this value to// authenticate with your backend server, if you have one. Use// FirebaseUser.getIdToken() instead.valuid=it.uid}
MainActivity.kt

Java

FirebaseUseruser=FirebaseAuth.getInstance().getCurrentUser();if(user!=null){// Name, email address, and profile photo UrlStringname=user.getDisplayName();Stringemail=user.getEmail();UriphotoUrl=user.getPhotoUrl();// Check if user's email is verifiedbooleanemailVerified=user.isEmailVerified();// The user's ID, unique to the Firebase project. Do NOT use this value to// authenticate with your backend server, if you have one. Use// FirebaseUser.getIdToken() instead.Stringuid=user.getUid();}
MainActivity.java

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 getProviderData method. For example:

Kotlin

valuser=Firebase.auth.currentUseruser?.let{for(profileinit.providerData){// Id of the provider (ex: google.com)valproviderId=profile.providerId// UID specific to the providervaluid=profile.uid// Name, email address, and profile photo Urlvalname=profile.displayNamevalemail=profile.emailvalphotoUrl=profile.photoUrl}}
MainActivity.kt

Java

FirebaseUseruser=FirebaseAuth.getInstance().getCurrentUser();if(user!=null){for(UserInfoprofile:user.getProviderData()){// Id of the provider (ex: google.com)StringproviderId=profile.getProviderId();// UID specific to the providerStringuid=profile.getUid();// Name, email address, and profile photo UrlStringname=profile.getDisplayName();Stringemail=profile.getEmail();UriphotoUrl=profile.getPhotoUrl();}}
MainActivity.java

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 updateProfile method. For example:

Kotlin

valuser=Firebase.auth.currentUservalprofileUpdates=userProfileChangeRequest{displayName="Jane Q. User"photoUri=Uri.parse("https://example.com/jane-q-user/profile.jpg")}user!!.updateProfile(profileUpdates).addOnCompleteListener{task-> if(task.isSuccessful){Log.d(TAG,"User profile updated.")}}
MainActivity.kt

Java

FirebaseUseruser=FirebaseAuth.getInstance().getCurrentUser();UserProfileChangeRequestprofileUpdates=newUserProfileChangeRequest.Builder().setDisplayName("Jane Q. User").setPhotoUri(Uri.parse("https://example.com/jane-q-user/profile.jpg")).build();user.updateProfile(profileUpdates).addOnCompleteListener(newOnCompleteListener<Void>(){@OverridepublicvoidonComplete(@NonNullTask<Void>task){if(task.isSuccessful()){Log.d(TAG,"User profile updated.");}}});
MainActivity.java

Set a user's email address

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

Kotlin

valuser=Firebase.auth.currentUseruser!!.updateEmail("user@example.com").addOnCompleteListener{task-> if(task.isSuccessful){Log.d(TAG,"User email address updated.")}}
MainActivity.kt

Java

FirebaseUseruser=FirebaseAuth.getInstance().getCurrentUser();user.updateEmail("user@example.com").addOnCompleteListener(newOnCompleteListener<Void>(){@OverridepublicvoidonComplete(@NonNullTask<Void>task){if(task.isSuccessful()){Log.d(TAG,"User email address updated.");}}});
MainActivity.java

Send a user a verification email

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

Kotlin

valuser=Firebase.auth.currentUseruser!!.sendEmailVerification().addOnCompleteListener{task-> if(task.isSuccessful){Log.d(TAG,"Email sent.")}}
MainActivity.kt

Java

FirebaseAuthauth=FirebaseAuth.getInstance();FirebaseUseruser=auth.getCurrentUser();user.sendEmailVerification().addOnCompleteListener(newOnCompleteListener<Void>(){@OverridepublicvoidonComplete(@NonNullTask<Void>task){if(task.isSuccessful()){Log.d(TAG,"Email sent.");}}});
MainActivity.java

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:

Kotlin

auth.setLanguageCode("fr")// To apply the default app language instead of explicitly setting it.// auth.useAppLanguage()
MainActivity.kt

Java

auth.setLanguageCode("fr");// To apply the default app language instead of explicitly setting it.// auth.useAppLanguage();
MainActivity.java

Set a user's password

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

Kotlin

valuser=Firebase.auth.currentUservalnewPassword="SOME-SECURE-PASSWORD"user!!.updatePassword(newPassword).addOnCompleteListener{task-> if(task.isSuccessful){Log.d(TAG,"User password updated.")}}
MainActivity.kt

Java

FirebaseUseruser=FirebaseAuth.getInstance().getCurrentUser();StringnewPassword="SOME-SECURE-PASSWORD";user.updatePassword(newPassword).addOnCompleteListener(newOnCompleteListener<Void>(){@OverridepublicvoidonComplete(@NonNullTask<Void>task){if(task.isSuccessful()){Log.d(TAG,"User password updated.");}}});
MainActivity.java

Send a password reset email

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

Kotlin

valemailAddress="user@example.com"Firebase.auth.sendPasswordResetEmail(emailAddress).addOnCompleteListener{task-> if(task.isSuccessful){Log.d(TAG,"Email sent.")}}
MainActivity.kt

Java

FirebaseAuthauth=FirebaseAuth.getInstance();StringemailAddress="user@example.com";auth.sendPasswordResetEmail(emailAddress).addOnCompleteListener(newOnCompleteListener<Void>(){@OverridepublicvoidonComplete(@NonNullTask<Void>task){if(task.isSuccessful()){Log.d(TAG,"Email sent.");}}});
MainActivity.java

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:

Kotlin

auth.setLanguageCode("fr")// To apply the default app language instead of explicitly setting it.// auth.useAppLanguage()
MainActivity.kt

Java

auth.setLanguageCode("fr");// To apply the default app language instead of explicitly setting it.// auth.useAppLanguage();
MainActivity.java

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:

Kotlin

valuser=Firebase.auth.currentUser!!user.delete().addOnCompleteListener{task-> if(task.isSuccessful){Log.d(TAG,"User account deleted.")}}
MainActivity.kt

Java

FirebaseUseruser=FirebaseAuth.getInstance().getCurrentUser();user.delete().addOnCompleteListener(newOnCompleteListener<Void>(){@OverridepublicvoidonComplete(@NonNullTask<Void>task){if(task.isSuccessful()){Log.d(TAG,"User account deleted.");}}});
MainActivity.java

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 FirebaseAuthRecentLoginRequiredException. When this happens, re-authenticate the user by getting new sign-in credentials from the user and passing the credentials to reauthenticate. For example:

Kotlin

valuser=Firebase.auth.currentUser!!// Get auth credentials from the user for re-authentication. The example below shows// email and password credentials but there are multiple possible providers,// such as GoogleAuthProvider or FacebookAuthProvider.valcredential=EmailAuthProvider.getCredential("user@example.com","password1234")// Prompt the user to re-provide their sign-in credentialsuser.reauthenticate(credential).addOnCompleteListener{Log.d(TAG,"User re-authenticated.")}
MainActivity.kt

Java

FirebaseUseruser=FirebaseAuth.getInstance().getCurrentUser();// Get auth credentials from the user for re-authentication. The example below shows// email and password credentials but there are multiple possible providers,// such as GoogleAuthProvider or FacebookAuthProvider.AuthCredentialcredential=EmailAuthProvider.getCredential("user@example.com","password1234");// Prompt the user to re-provide their sign-in credentialsuser.reauthenticate(credential).addOnCompleteListener(newOnCompleteListener<Void>(){@OverridepublicvoidonComplete(@NonNullTask<Void>task){Log.d(TAG,"User re-authenticated.");}});
MainActivity.java

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:

firebaseauth:importusers.json--hash-algo=scrypt--rounds=8--mem-cost=14