Anonymous authentication in Firebase - Mini Project: Build & Apply

Anonymous Authentication with Firebase

📖 Scenario: You are building a simple app that lets users try it without signing up. This is called anonymous authentication. It helps users explore your app quickly.

🎯 Goal: Create a Firebase project setup that allows users to sign in anonymously. You will write code to initialize Firebase, enable anonymous sign-in, and handle the sign-in process.

📋 What You'll Learn

Initialize Firebase app with given config

Enable anonymous authentication in Firebase

Write code to sign in users anonymously

Handle sign-in success and failure

💡 Why This Matters

🌍 Real World

Anonymous authentication lets users try apps quickly without creating accounts. This improves user experience and can increase app engagement.

💼 Career

Understanding Firebase anonymous authentication is useful for frontend and backend developers working on user authentication and app onboarding.

1

Initialize Firebase App

Create a constant called firebaseConfig with the exact keys and values: apiKey: 'AIzaSyA-ExampleKey12345', authDomain: 'your-app.firebaseapp.com', projectId: 'your-app', storageBucket: 'your-app.appspot.com', messagingSenderId: '1234567890', appId: '1:1234567890:web:abcdef123456'. Then initialize Firebase app by calling initializeApp(firebaseConfig) and assign it to a constant called app.

Firebase

# Create firebaseConfig object and initialize Firebase app
# Your code here

Need a hint?

Use const firebaseConfig = { ... } with the exact keys and values. Then call initializeApp(firebaseConfig) and assign it to app.

2

Import and Setup Firebase Auth

Import getAuth and signInAnonymously from 'firebase/auth'. Create a constant called auth by calling getAuth(app).

Firebase

import { initializeApp } from 'firebase/app';
// Import getAuth and signInAnonymously from 'firebase/auth'

const firebaseConfig = {
  apiKey: 'AIzaSyA-ExampleKey12345',
  authDomain: 'your-app.firebaseapp.com',
  projectId: 'your-app',
  storageBucket: 'your-app.appspot.com',
  messagingSenderId: '1234567890',
  appId: '1:1234567890:web:abcdef123456'
};

const app = initializeApp(firebaseConfig);

// Create auth constant by calling getAuth(app)
# Your code here

Need a hint?

Import getAuth and signInAnonymously from 'firebase/auth'. Then create auth by calling getAuth(app).

3

Sign In Anonymously

Write a function called signInUserAnonymously that calls signInAnonymously(auth). Use .then() to handle success by receiving a userCredential parameter and accessing userCredential.user. Use .catch() to handle errors by receiving an error parameter.

Firebase

import { initializeApp } from 'firebase/app';
import { getAuth, signInAnonymously } from 'firebase/auth';

const firebaseConfig = {
  apiKey: 'AIzaSyA-ExampleKey12345',
  authDomain: 'your-app.firebaseapp.com',
  projectId: 'your-app',
  storageBucket: 'your-app.appspot.com',
  messagingSenderId: '1234567890',
  appId: '1:1234567890:web:abcdef123456'
};

const app = initializeApp(firebaseConfig);
const auth = getAuth(app);

// Write function signInUserAnonymously to sign in anonymously
# Your code here

Need a hint?

Create a function signInUserAnonymously. Inside, call signInAnonymously(auth). Use .then() to get userCredential and access userCredential.user. Use .catch() to handle errors.

4

Call Anonymous Sign-In Function

Call the function signInUserAnonymously() to start the anonymous sign-in process.

Firebase

import { initializeApp } from 'firebase/app';
import { getAuth, signInAnonymously } from 'firebase/auth';

const firebaseConfig = {
  apiKey: 'AIzaSyA-ExampleKey12345',
  authDomain: 'your-app.firebaseapp.com',
  projectId: 'your-app',
  storageBucket: 'your-app.appspot.com',
  messagingSenderId: '1234567890',
  appId: '1:1234567890:web:abcdef123456'
};

const app = initializeApp(firebaseConfig);
const auth = getAuth(app);

function signInUserAnonymously() {
  signInAnonymously(auth)
    .then((userCredential) => {
      const user = userCredential.user;
      // User signed in anonymously
    })
    .catch((error) => {
      // Handle error
    });
}

// Call the signInUserAnonymously function
# Your code here

Need a hint?

Simply call signInUserAnonymously() to start the anonymous sign-in.