Managing Unregistered Emails with Firebase Authentication

Enhancing Firebase Authentication's Email Verification

Android Java Implementation

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseAuthUserCollisionException;
import android.widget.Toast;
// Initialize Firebase Auth
FirebaseAuth fAuth = FirebaseAuth.getInstance();
String emailInput = email.getEditText().getText().toString();
// Check if the user exists before sending a password reset email
fAuth.fetchSignInMethodsForEmail(emailInput).addOnCompleteListener(task -> {
    if (task.isSuccessful()) {
        List<String> signInMethods = task.getResult().getSignInMethods();
        if (signInMethods != null && !signInMethods.isEmpty()) {
            fAuth.sendPasswordResetEmail(emailInput)
                .addOnCompleteListener(resetTask -> {
                    if (resetTask.isSuccessful()) {
                        NewFragment newFragment = new NewFragment();
                        loadFragment(newFragment);
                    }
                });
        } else {
            email.setError(getString(R.string.email_not_assigned));
        }
    } else {
        Toast.makeText(getContext(), "Error checking user", Toast.LENGTH_SHORT).show();
    }
});

Validation of Email Reset Requests on the Server Side

Using Firebase Admin SDK with Node.js

const admin = require('firebase-admin');
const serviceAccount = require('/path/to/serviceAccountKey.json');
// Initialize Firebase Admin
admin.initializeApp({
  credential: admin.credential.cert(serviceAccount)
});
let emailInput = 'user@example.com';
// Check if the email is registered in Firebase
admin.auth().getUserByEmail(emailInput)
  .then(userRecord => {
    admin.auth().sendPasswordResetEmail(emailInput)
      .then(() => console.log('Password reset email sent'))
      .catch(error => console.error('Error sending reset email', error));
  })
  .catch(error => {
    console.error('No user found with this email', error);
  });

Frequent Questions about Email Verification on Firebase

1. When sending a password reset, is there a way to find out if an email address is registered with Firebase?
2. To confirm the presence of an email, apply the fetchSignInMethodsForEmail technique. The email is registered if the list that is returned is not empty.
3. How do I send a password reset to an email address that isn't registered?
4. The operation is not reported as successful and Firebase fails to send the email; you should handle this circumstance in your code.
5. Is it feasible to alter the email Firebase sends out with a password reset?
6. Indeed, you may alter the email template by going to the Authentication settings section of the Firebase UI.
7. Can email password resets from Firebase be sent to addresses that weren't validated during registration?
8. Yes, Firebase is able to send the reset email as long as it is linked to an active account.
9. What should I do if the email requesting a password reset doesn't go through?
10. In order to notify the user of the failure, incorporate error handling into the addOnCompleteListener method.

Last Words on Firebase Email Authentication

Ensuring the integrity and security of an application requires that any instructions for password resets are sent after a check for existing user accounts. It guarantees that only authorized users receive emails requesting password resets and stops illegal attempts to access user accounts. In addition to improving user experience and securing the system, this method keeps users from entering wrong information and saves them from needless confusion and irritation.