Get Started with Firebase Authentication on Websites

You can use Firebase Authentication to allow users to sign in to your app using one or more sign-in methods, including email address and password sign-in, and federated identity providers such as Google Sign-in and Facebook Login. This tutorial gets you started with Firebase Authentication by showing you how to add email address and password sign-in to your app.

Connect your app to Firebase

Install the Firebase SDK. Be sure to paste the configuration code into your web page as described.

Sign up new users

Create a form that allows new users to register with your app using their email address and a password. When a user completes the form, validate the email address and password provided by the user, then pass them to the createUserWithEmailAndPassword method:

firebase.auth().createUserWithEmailAndPassword(email, password)
  .then((user) => {
    // Signed in 
    // ...
  })
  .catch((error) => {
    var errorCode = error.code;
    var errorMessage = error.message;
    // ..
  });email.js

Sign in existing users

Create a form that allows existing users to sign in using their email address and password. When a user completes the form, call the signInWithEmailAndPassword method:

firebase.auth().signInWithEmailAndPassword(email, password)
  .then((user) => {
    // Signed in 
    // ...
  })
  .catch((error) => {
    var errorCode = error.code;
    var errorMessage = error.message;
  });email.js

Set an authentication state observer and get user data

For each of your app's pages that need information about the signed-in user, attach an observer to the global authentication object. This observer gets called whenever the user's sign-in state changes.

Attach the observer using the onAuthStateChanged method. When a user successfully signs in, you can get information about the user in the observer.

firebase.auth().onAuthStateChanged((user) => {
  if (user) {
    // User is signed in, see docs for a list of available properties
    // https://firebase.google.com/docs/reference/js/firebase.User
    var uid = user.uid;
    // ...
  } else {
    // User is signed out
    // ...
  }
});index.js

Next steps

Learn how to add support for other identity providers and anonymous guest accounts: