How to fix auth/invalid-email in Firebase

FirebaseBEGINNERLOW

The auth/invalid-email error occurs when an email address is not properly formatted or contains invalid characters. Fix it by validating and trimming email input before passing it to Firebase authentication methods.

What this error means

Firebase throws this error when you attempt to authenticate using an email address that does not conform to the standard email format. This is a client-side validation error that Firebase enforces to ensure only valid email addresses can be used for authentication. The error is triggered by the Firebase SDK when creating a user account, signing in, or performing password resets with a malformed email address.

Typical symptoms

How to fix "auth/invalid-email"

1Trim and validate email input before authentication

The most common cause is whitespace in the email field. Always clean user input before sending to Firebase:

JavaScript/Web SDK:

javascript

const email = userInput.trim().toLowerCase();

try {
  await firebase.auth().signInWithEmailAndPassword(email, password);
} catch (error) {
  if (error.code === 'auth/invalid-email') {
    console.error('Invalid email format');
  }
}

TypeScript with Firebase Admin SDK:

typescript

const email = userInput.trim().toLowerCase();

try {
  const user = await admin.auth().getUserByEmail(email);
} catch (error) {
  if (error.code === 'auth-user-not-found') {
    // Different error when using Admin SDK
  }
}

iOS (Swift):

swift

let email = emailInput.trimmingCharacters(in: .whitespaces).lowercased()

Auth.auth().signIn(withEmail: email, password: password) { result, error in
  if let error = error as? NSError {
    if error.code == AuthErrorCode.invalidEmail.rawValue {
      print('Invalid email format')
    }
  }
}

Android (Kotlin):

kotlin

val email = emailInput.trim().toLowerCase()

FirebaseAuth.getInstance().signInWithEmailAndPassword(email, password)

.addOnFailureListener { exception ->

javascript

if (exception is FirebaseAuthInvalidUserException) {
      Log.e('Auth', 'Invalid email format')
    }
  }

2Check that you're passing string values, not objects

A common mistake when managing state is passing the entire state object instead of the string value:

WRONG - passing the entire email object:

javascript

const state = { email: { value: '[email protected]' } };
await firebase.auth().signInWithEmailAndPassword(state.email, password);
// Error: auth/invalid-email

CORRECT - passing only the string value:

javascript

await firebase.auth().signInWithEmailAndPassword(state.email.value, password);

WRONG with React hooks:

javascript

const [email, setEmail] = useState({});
await firebase.auth().signInWithEmailAndPassword(email, password);

CORRECT with React hooks:

javascript

const [email, setEmail] = useState('');
await firebase.auth().signInWithEmailAndPassword(email, password);

3Implement proper error handling for invalid email

Add specific error handling to distinguish invalid email from other authentication errors:

javascript

async function handleSignIn(email, password) {
  try {
    const email = email.trim().toLowerCase();
    await firebase.auth().signInWithEmailAndPassword(email, password);
  } catch (error) {
    if (error.code === 'auth/invalid-email') {
      // Email format is wrong
      showError('Please enter a valid email address (e.g., [email protected])');
    } else if (error.code === 'auth/user-not-found') {
      // Email format is valid but account doesn't exist
      showError('No account found with this email');
    } else if (error.code === 'auth/wrong-password') {
      // User exists but password is incorrect
      showError('Incorrect password');
    } else {
      showError('Authentication failed: ' + error.message);
    }
  }
}

4Add client-side email validation before Firebase calls

Validate email format locally before making Firebase requests to provide faster feedback:

Simple regex pattern for email validation:

javascript

function isValidEmail(email) {
  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
  return emailRegex.test(email);
}

async function signInUser(emailInput, password) {
  const email = emailInput.trim().toLowerCase();

  // Client-side validation first
  if (!isValidEmail(email)) {
    showError('Invalid email format');
    return;
  }

  try {
    await firebase.auth().signInWithEmailAndPassword(email, password);
  } catch (error) {
    handleAuthError(error);
  }
}

Using a library like email-validator:

javascript

import validator from 'email-validator';

const email = userInput.trim().toLowerCase();
if (!validator.validate(email)) {
  showError('Invalid email format');
  return;
}

How to fix auth/invalid-email in Firebase

What this error means

Typical symptoms

Common causes

How to fix "auth/invalid-email"

Advanced notes

Related errors

Official resources & further reading