Authenticate with Firebase using Password-Based Accounts on Android

You can use Firebase Authentication to let your users authenticate with Firebase using their email addresses and passwords, and to manage your app's password-based accounts.

Before you begin

  1. If you haven't already, add Firebase to your Android project.

  2. If you haven't yet connected your app to your Firebase project, do so from the Firebase console.
  3. Enable Email/Password sign-in:
    1. In the Firebase console, open the Auth section.
    2. On the Sign in method tab, enable the Email/password sign-in method and click Save.

  4. In your module (app-level) Gradle file (usually <project>/<app-module>/build.gradle.kts or <project>/<app-module>/build.gradle), add the dependency for the Firebase Authentication library for Android. We recommend using the Firebase Android BoM to control library versioning. 

    dependencies {
    // Import the BoM for the Firebase platform
    implementation(platform("com.google.firebase:firebase-bom:33.5.1"))

    // Add the dependency for the Firebase Authentication library
    // When using the BoM, you don't specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-auth")
}

    By using the Firebase Android BoM, your app will always use compatible versions of Firebase Android libraries.

    (Alternative)  Add Firebase library dependencies without using the BoM

    If you choose not to use the Firebase BoM, you must specify each Firebase library version in its dependency line.

    Note that if you use multiple Firebase libraries in your app, we strongly recommend using the BoM to manage library versions, which ensures that all versions are compatible. 

    dependencies {
    // Add the dependency for the Firebase Authentication library
    // When NOT using the BoM, you must specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-auth:23.1.0")
}
         Looking for a Kotlin-specific library module? Starting in October 2023 (Firebase BoM 32.5.0), both Kotlin and Java developers can depend on the main library module (for details, see the FAQ about this initiative).

Create a password-based account

To create a new user account with a password, complete the following steps in your app's sign-in activity:

  1. In your sign-up activity's onCreate method, get the shared instance of the FirebaseAuth object:

    Kotlin+KTX

    private lateinit var auth: FirebaseAuth
// ...
// Initialize Firebase Auth
auth = Firebase.auth
    EmailPasswordActivity.kt

    Java

    private FirebaseAuth mAuth;
// ...
// Initialize Firebase Auth
mAuth = FirebaseAuth.getInstance();
    EmailPasswordActivity.java
  2. When initializing your Activity, check to see if the user is currently signed in:

    Kotlin+KTX

    public override fun onStart() {
    super.onStart()
    // Check if user is signed in (non-null) and update UI accordingly.
    val currentUser = auth.currentUser
    if (currentUser != null) {
        reload()
    }
}
    EmailPasswordActivity.kt

    Java

    @Override
public void onStart() {
    super.onStart();
    // Check if user is signed in (non-null) and update UI accordingly.
    FirebaseUser currentUser = mAuth.getCurrentUser();
    if(currentUser != null){
        reload();
    }
}
    EmailPasswordActivity.java
  3. When a new user signs up using your app's sign-up form, complete any new account validation steps that your app requires, such as verifying that the new account's password was correctly typed and meets your complexity requirements.
  4. Create a new account by passing the new user's email address and password to createUserWithEmailAndPassword:

    Kotlin+KTX

    auth.createUserWithEmailAndPassword(email, password)
    .addOnCompleteListener(this) { task ->
        if (task.isSuccessful) {
            // Sign in success, update UI with the signed-in user's information
            Log.d(TAG, "createUserWithEmail:success")
            val user = auth.currentUser
            updateUI(user)
        } else {
            // If sign in fails, display a message to the user.
            Log.w(TAG, "createUserWithEmail:failure", task.exception)
            Toast.makeText(
                baseContext,
                "Authentication failed.",
                Toast.LENGTH_SHORT,
            ).show()
            updateUI(null)
        }
    }
    EmailPasswordActivity.kt

    Java

    mAuth.createUserWithEmailAndPassword(email, password)
        .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
            @Override
            public void onComplete(@NonNull Task<AuthResult> task) {
                if (task.isSuccessful()) {
                    // Sign in success, update UI with the signed-in user's information
                    Log.d(TAG, "createUserWithEmail:success");
                    FirebaseUser user = mAuth.getCurrentUser();
                    updateUI(user);
                } else {
                    // If sign in fails, display a message to the user.
                    Log.w(TAG, "createUserWithEmail:failure", task.getException());
                    Toast.makeText(EmailPasswordActivity.this, "Authentication failed.",
                            Toast.LENGTH_SHORT).show();
                    updateUI(null);
                }
            }
        });
    EmailPasswordActivity.java
    If the new account was created, the user is also signed in. In the callback, you can use the getCurrentUser method to get the user's account data.

Sign in a user with an email address and password

The steps for signing in a user with a password are similar to the steps for creating a new account. In your app's sign-in activity, do the following:

  1. In your sign-in activity's onCreate method, get the shared instance of the FirebaseAuth object:

    Kotlin+KTX

    private lateinit var auth: FirebaseAuth
// ...
// Initialize Firebase Auth
auth = Firebase.auth
    EmailPasswordActivity.kt

    Java

    private FirebaseAuth mAuth;
// ...
// Initialize Firebase Auth
mAuth = FirebaseAuth.getInstance();
    EmailPasswordActivity.java
  2. When initializing your Activity, check to see if the user is currently signed in:

    Kotlin+KTX

    public override fun onStart() {
    super.onStart()
    // Check if user is signed in (non-null) and update UI accordingly.
    val currentUser = auth.currentUser
    if (currentUser != null) {
        reload()
    }
}
    EmailPasswordActivity.kt

    Java

    @Override
public void onStart() {
    super.onStart();
    // Check if user is signed in (non-null) and update UI accordingly.
    FirebaseUser currentUser = mAuth.getCurrentUser();
    if(currentUser != null){
        reload();
    }
}
    EmailPasswordActivity.java
  3. When a user signs in to your app, pass the user's email address and password to signInWithEmailAndPassword:

    Kotlin+KTX

    auth.signInWithEmailAndPassword(email, password)
    .addOnCompleteListener(this) { task ->
        if (task.isSuccessful) {
            // Sign in success, update UI with the signed-in user's information
            Log.d(TAG, "signInWithEmail:success")
            val user = auth.currentUser
            updateUI(user)
        } else {
            // If sign in fails, display a message to the user.
            Log.w(TAG, "signInWithEmail:failure", task.exception)
            Toast.makeText(
                baseContext,
                "Authentication failed.",
                Toast.LENGTH_SHORT,
            ).show()
            updateUI(null)
        }
    }
    EmailPasswordActivity.kt

    Java

    mAuth.signInWithEmailAndPassword(email, password)
        .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
            @Override
            public void onComplete(@NonNull Task<AuthResult> task) {
                if (task.isSuccessful()) {
                    // Sign in success, update UI with the signed-in user's information
                    Log.d(TAG, "signInWithEmail:success");
                    FirebaseUser user = mAuth.getCurrentUser();
                    updateUI(user);
                } else {
                    // If sign in fails, display a message to the user.
                    Log.w(TAG, "signInWithEmail:failure", task.getException());
                    Toast.makeText(EmailPasswordActivity.this, "Authentication failed.",
                            Toast.LENGTH_SHORT).show();
                    updateUI(null);
                }
            }
        });
    EmailPasswordActivity.java
    If sign-in succeeded, you can use the returned FirebaseUser to proceed.

Recommended: Set a password policy

You can improve account security by enforcing password complexity requirements.

To configure a password policy for your project, open the Password policy tab on the Authentication Settings page of the Firebase console:

Authentication Settings

Firebase Authentication password policies support the following password requirements:

  • Lowercase character required

  • Uppercase character required

  • Numeric character required

  • Non-alphanumeric character required

    The following characters satisfy the non-alphanumeric character requirement: ^ $ * . [ ] { } ( ) ? " ! @ # % & / \ , > < ' : ; | _ ~

  • Minimum password length (ranges from 6 to 30 characters; defaults to 6)

  • Maximum password length (maximum length of 4096 characters)

You can enable password policy enforcement in two modes:

  • Require: Attempts to sign up fail until the user updates to a password that complies with your policy.

  • Notify: Users are allowed to sign up with a non-compliant password. When using this mode, you should check if the user's password complies with the policy on the client side and prompt the user in some way to update their password if it does not comply.

New users are always required to choose a password that complies with your policy.

If you have active users, we recommend not enabling force upgrade on sign in unless you intend to block access to users whose passwords don't comply with your policy. Instead, use notify mode, which allows users to sign in with their current passwords, and inform them of the requirements their password lacks.

Recommended: Enable email enumeration protection

Some Firebase Authentication methods that take email addresses as parameters throw specific errors if the email address is unregistered when it must be registered (for example, when signing in with an email address and password), or registered when it must be unused (for example, when changing a user's email address). While this can be helpful for suggesting specific remedies to users, it can also be abused by malicious actors to discover the email addresses registered by your users.

To mitigate this risk, we recommend you enable email enumeration protection for your project using the Google Cloud gcloud tool. Note that enabling this feature changes Firebase Authentication's error reporting behavior: be sure your app doesn't rely on the more specific errors.

Next steps

After a user signs in for the first time, a new user account is created and linked to the credentials—that is, the user name and password, phone number, or auth provider information—the user signed in with. This new account is stored as part of your Firebase project, and can be used to identify a user across every app in your project, regardless of how the user signs in.

  • In your apps, you can get the user's basic profile information from the FirebaseUser object. See Manage Users.

  • In your Firebase Realtime Database and Cloud Storage Security Rules, you can get the signed-in user's unique user ID from the auth variable, and use it to control what data a user can access.

You can allow users to sign in to your app using multiple authentication providers by linking auth provider credentials to an existing user account.

To sign out a user, call signOut:

Kotlin+KTX

Firebase.auth.signOut()
MainActivity.kt

Java

FirebaseAuth.getInstance().signOut();
MainActivity.java