Next.js Phone Authentication with Firebase

Next.js Phone Authentication with Firebase

In this digital age, authentication is an integral part of any web application. While traditional email and password authentication is still widely used, phone authentication is becoming increasingly popular due to its ease and security. In this blog, we will explore how to implement phone authentication with Firebase in a Next.js application.

Before diving into the implementation details, let's first understand what Next.js and Firebase are and why it's a great choice for your web application.

What is Next.js?

Next.js is a popular open-source React framework used for building web applications. It enables developers to build server-side rendered React applications with ease. Next.js comes with a number of built-in features, such as automatic code splitting, server-side rendering, static file serving, and client-side routing, which help to make the development process faster and more efficient. Additionally, Next.js also offers support for various data fetching strategies, including static generation and server-side rendering, which can help improve the performance of web applications. Overall, Next.js is a powerful and flexible framework that can be used to build a wide range of web applications, from simple static websites to complex dynamic web applications.

What is Firebase?

Firebase is a mobile and web application development platform owned by Google that provides developers with a range of tools and services to help them build high-quality apps quickly and easily. Firebase provides a variety of features, including a real-time database, cloud messaging, authentication, hosting, storage, and analytics. These features enable developers to focus on building their apps rather than worrying about backend infrastructure, server maintenance, and scalability. Firebase is designed to be easy to use, so developers can get started quickly, and it is also highly scalable, allowing apps to grow and handle large numbers of users. Overall, Firebase is a powerful and flexible platform that can be used to build a wide range of applications, from small personal projects to large-scale enterprise solutions.

Now let's jump right into it.

Step 1: Install Node.js

If you haven't already, install Node.js on your machine.

Step 2: Create a new Next.js app

Open up your terminal and navigate to the directory where you want to create your new app. Then, run the following command:

npx create-next-app my-app

Replace my-app with the name of your app.

Step 3: Start the development server

Navigate into your new app's directory by running:

cd my-app

Then, start the development server with:

npm run dev

You should now see your app running at http://localhost:3000 in your browser!

Step 4: Set up a Firebase project

First, you'll need to create a Firebase project. Go to the Firebase Console and create a new project. Once your project is created, go to the Authentication tab and enable the Phone sign-in method.

Step 5: Install Firebase

To use Firebase in your Next.js app, you'll need to install the Firebase and Firebase UI packages. You can do this using npm:

npm install firebase

Step 6: Add Firebase configuration to your app

In your Next.js app, create a new file called firebase.js and add the following code:

import firebase from 'firebase/app';
import 'firebase/auth';

const firebaseConfig = {
  // Your Firebase configuration goes here

if (!firebase.apps.length) {

export default firebase;

Replace // Your Firebase configuration goes here with your actual Firebase configuration, which you can find in the Firebase console under Project settings > General > Your apps > Firebase SDK snippet > Config.

Step 7: Create the phone authentication component

In your Next.js app, create a new component called PhoneAuth.js and add the following code:

import React, { useState } from 'react';
import firebase from '../firebase';

const PhoneAuth = () => {
  const [phoneNumber, setPhoneNumber] = useState('');
  const [verificationCode, setVerificationCode] = useState('');
  const [verificationId, setVerificationId] = useState('');

  const handleSendCode = () => {
    const recaptchaVerifier = new firebase.auth.RecaptchaVerifier('send-code-button', {
      size: 'invisible',

    firebase.auth().signInWithPhoneNumber(phoneNumber, recaptchaVerifier)
      .then((verificationId) => {
      .catch((error) => {

  const handleVerifyCode = () => {
    const credential = firebase.auth.PhoneAuthProvider.credential(verificationId, verificationCode);

      .then((userCredential) => {
        // User signed in successfully
      .catch((error) => {

  return (
      <input type="tel" value={phoneNumber} onChange={(e) => setPhoneNumber(} />
      <button id="send-code-button" onClick={handleSendCode}>Send Code</button>
      <input type="text" value={verificationCode} onChange={(e) => setVerificationCode(} />
      <button onClick={handleVerifyCode}>Verify Code</button>

export default PhoneAuth;

This component creates a form with two inputs: one for the phone number and one for the verification code. When the user clicks the "Send Code" button, Firebase sends a verification code to the user's phone number. When the user enters the code and clicks the "Verify Code" button, Firebase verifies the code and signs the user in.

Step 8: Add the phone authentication component to your app

Finally, add the PhoneAuth component to your Next.js app wherever you want to display the phone authentication form.

import PhoneAuth from '../components/PhoneAuth';

const LoginPage = () => {
  return (
      <PhoneAuth />

export default LoginPage;

And that's it! With just a few simple steps, you can add phone authentication to your Next.js app using Firebase. Happy coding!


In this blog post, we have seen how easy it is to add phone authentication to a Next.js app using Firebase. With Firebase's secure and reliable authentication service, you can ensure that your users' data is safe and protected.

By following the steps outlined in this blog post, you can quickly and easily integrate phone authentication into your Next.js app. Whether you are building a login system, a verification process, or any other feature that requires phone authentication, Firebase makes it easy to get started.

So why wait? Add phone authentication to your Next.js app today and take your app to the next level of security and functionality.

Happy coding!