Sunday December 27, 2020 By David Quintanilla
Authenticating React Apps With Auth0 — Smashing Magazine

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Nefe is a Frontend Developer who enjoys studying new issues and sharing his data with others.
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An essential facet of app growth is making certain that solely verified customers have entry to our apps. This may be tedious and expensive do, particularly if you add various strategies of logging in exterior emails and passwords. Auth0 is a service that gives authentication functionalities to builders out of the field.

On this article, we’ll learn to authenticate our React apps utilizing Auth0. We may even learn to arrange Social Logins in our apps. This text will probably be useful to readers who wish to add some type of authentication to their apps or wish to get conversant in Auth0.

Authentication is a important facet of most apps, as builders should make sure the apps they construct are safe and may solely be accessed by verified customers. Whereas customized authentication options could be constructed, the fee and sources concerned to construct, keep, host, and safe them could be heavy. That is the place Auth0 is available in.

Auth0 supplies SDKs for all well-liked internet, cellular, and native platforms, permitting for deep integration with the language and stack of your desire. You may as well arrange completely different login choices so your customers can login to your app with their most well-liked technique.

This text doesn’t cowl an in-depth rationalization of how authentication works beneath the hood. Auth0 has a resource that covers that.

Word: To observe alongside, you’ll want a fundamental understanding of React and React Hooks.

What Is Auth0?

Auth0 is a versatile answer so as to add authentication and authorization to your apps. You may join any app to Auth0 and outline the id suppliers you wish to use, whether or not Google, Fb, Github or others. Each time a person logs into your app, Auth0 will confirm their id and ship the authentication information again to your app.

Whereas Auth0 comes with with completely different login varieties, their Common Login is the most secure and sooner to get began with. Auth0 additionally recommends you employ this. With Common Login, the person is redirected to the login web page, authenticated by Auth0’s servers, after which they’re redirected again to your app. When utilizing Common Login, you can begin off utilizing a easy username and password, and in a while, add different login strategies, based mostly in your app’s necessities.

One other advantage of utilizing Common Login is that you simply don’t must arrange a customized login web page. Nevertheless, you possibly can customise the Common Login to fit your wants.

How Does Auth0 Work?

When Auth0’s servers redirect a person again to your app, the redirect URL is populated with details about the authenticated person. This permits us to entry information in regards to the person from the data we get again from the id supplier. A person profile in Auth0 is the data obtained from an id supplier. The person information we get again will differ from one id supplier to a different.

When the person is redirected again to the app, the data despatched alongside within the redirect URL is as follows:

  • entry token
    That is used to tell an API that the bearer of the token is permitted to entry the API and carry out some motion. Entry tokens usually are not supposed to hold details about the person. They’re solely used to authorize entry to a useful resource.
  • id token
    It is a safety token granted by the OpenID Supplier that incorporates details about a person. This data tells your consumer app that the person is authenticated, and can even offer you data like their username. It is available in JSON Web Token (JWT) format.
  • expires in
    This tells us what number of seconds till the entry token is now not legitimate. By default, that is 1200 seconds (20 minutes). When the entry token expires, the app will probably be compelled to make the person register once more.
  • scope
    OpenID Join (OIDC) scopes are utilized by an app throughout authentication to authorize entry to a person’s particulars, like title and film. Every scope returns a set of person attributes, that are known as claims. The scopes an app ought to request rely on which person attributes the app wants. As soon as the person authorizes the requested scopes, the claims are returned in an ID Token and are additionally obtainable by the /userinfo endpoint.

Auth0 Authentication Strategies

Auth0 supplies a number of platform integrations. On this article, we are going to check out the JavaScript SDK and the React SDK.

  • JavaScript SDK: It is a client-side JavaScript toolkit for Auth0 API.
  • React SDK: The Auth0 React SDK (auth0-react.js) is a JavaScript library for implementing authentication and authorization in React apps with Auth0.

Configuring Your Auth0 App

Your Auth0 dashboard
Your Auth0 dashboard. (Large preview)
  • Choose the kind of app. Ours is a SPA.
Choose app type
Select app sort. (Large preview)
Choose technology
Select know-how. (Large preview)
  • Pay attention to your app credentials. We’ll want them to combine Auth0 into our react app.
app credentials
App credentials. (Large preview)

We configure the URLs of the app in its settings for the login and logout performance to work correctly.

A callback URL is a URL in your app the place Auth0 redirects the person after they’ve authenticated. For our app, set the Allowed Callback URL to http://localhost:3000.

After Auth0 logs the person out of the authorization server, the logout URL is the URL the person is redirected to. We additionally set this to http://localhost:3000. Callback URLs could be manipulated by unauthorized events, so Auth0 acknowledges solely URLs within the Allowed Callback URLs discipline of an app’s Settings as legitimate.

Allowed Net Origins handles checking for present authentication periods. This ensures the person login persists after they depart your app or refresh the web page. We additionally set this to http://localhost:3000.

Authentication Utilizing Auth0 JavaScript SDK

Let’s use this SDK to simulate a fundamental Auth0 login move. The supply code for this part is on the market on GitHub. The parts of this demo app are:

  • App.js: that is the basis part. We go the Auth class we are going to create later to every part from right here.
  • Nav.js: it will comprise the login and logout buttons, serving to the person correctly navigate from one web page to a different.
  • Profile.js: the person profile. It’ll solely be accessible if the person has logged into the app.
  • Dwelling.js: the Dwelling part.
  • Auth.js: we outline the authentication utilities right here in an Auth class we are going to outline.
  • Callback.js: the part Auth0 redirects the person to as soon as they login.

Let’s arrange our app’s credentials as surroundings variables.


Create a .env to retailer the area and cleintId credentials of your app. Additionally, set the callback URL within the file. On this app, I will probably be utilizing http://localhost:3000 as my callback URL.

Including Auth0 Occasion

npm i auth0-js
import auth0 from 'auth0-js';

To make use of the JavaScript SDK in our app we, first set up the SDK. Subsequent, we create an Auth.js file the place we arrange the authentication performance. Import auth0 from auth0-js into the Auth.js file.

export default class Auth {
  constructor(historical past){
    this.historical past = historical past;
    this.auth0 = new auth0.WebAuth({
      area: course of.env.REACT_APP_AUTH0_DOMAIN,
      clientID: course of.env.REACT_APP_AUTH0_CLIENTID,
      redirectUri: course of.env.REACT_APP_AUTH0_CALLBACK_URL,
      responseType: "token id_token",
      scope: "openid profile e-mail"

Subsequent, we initialize a brand new occasion of the Auth0 app. To do that, create a category known as Auth. Right here, we initialize a brand new Auth0 occasion. We go in an choices object that incorporates some parameters.

There are a number of parameters we are able to add to the Auth0 occasion, and of these parameters, solely the area and clientID are required.

  • area: your Auth0 account area.
  • clientID: your Auth0 consumer ID.
  • redirectUri: the URL Auth0 redirects your person after they have been authenticated. By default the URL you specified in your app’s Callback URL will probably be used, so this parameter just isn’t required.
  • responseType: we outline the response we wish to get again from Auth0 when it authenticates our person. We specify that we wish to get the id_token again from the response.
  • scope: we outline what data we wish to get from the person. This manner, we can entry their e-mail handle and no matter data is saved of their profile. The knowledge we can get from the person depends upon the id supplier they use to register. We will probably be making use of the OpenID Connect protocol to entry details about the person.

The Auth class accepts react-router’s historical past prop as an argument. Afterward, we are going to use this to redirect the person to completely different pages in our app.

We create a brand new occasion of auth0 and go within the configurations. We assign the brand new occasion to this.auth0. We get values of area, clientID and redirectUri are from the .env file we created earlier.

Including Login Performance

We have to add a login technique to the category we created in Auth.js.

login = () => {

To do this, we add Auth0’s authorize() technique to login. authorize() is used for logging in customers by the Common Login. When authorize() is known as, it redirects the person to Auth0’s login web page.

The Auth class must the handed to different parts, the Nav, Dwelling and Callback parts.

import Auth from './Auth';

perform App({historical past}) {
  const auth = new Auth(historical past) 
  return (
    <div className="App">
      <Nav auth={auth}/>
        <div className="physique">
          <Route precise path="/" render={props => <Dwelling auth={auth} {...props} />} />
          <Route precise path="/callback" render={props => <Callback auth={auth} {...props} />} />
          <Route precise path="/profile" render={props => <Profile auth={auth} {...props} />} /> 

export default withRouter(App);

Right here, we create a brand new occasion of the Auth class and go it to the parts that want it as a prop.

Because the Auth class wants historical past, we’ll make use of withRouter so we are able to be capable to entry history.

import { Hyperlink } from 'react-router-dom' 

const Nav = ({auth}) => {
  return (
        <li><Hyperlink to="/">Dwelling</Hyperlink></li>
          <button onClick={auth.login}>log in</button>
export default Nav

Now that we’ve outlined the login() technique, we are able to use it within the login button. The person will probably be redirected to Auth0’s login web page after which to the callback URL as soon as they’ve been authenticated.

Subsequent, we’ve to create the part the person will get redirected to as soon as they log in.

import React from 'react'

const Callback = () => {
  return (
      <h1>I'm the callback part</h1>
export default Callback

Create a Callback.js file, and arrange a Callback part in it. Now when the person logs in, they’re redirected to the Callback part.

Dealing with Authentication

When Auth0 redirects the person again to the app, it sends alongside some authentication information within the callback URL. This information incorporates encoded details about the authenticated person.
To entry the information Auth0 sends again within the redirect URL, we arrange a handleAuth() technique within the Auth class. This technique will probably be known as within the Callback part.

handleAuth = () => {
    this.auth0.parseHash((err, authResult) => {
      if(authResult && authResult.accessToken && authResult.idToken) {
        this.historical past.push("/");
      } else if (err) {
        alert(`Error: ${err.error}`)

After the person is redirected, we are able to use the parseHash technique to parse the data that’s despatched again alongside within the callback URL. After parsing, we get again an error object and an authResult. We verify to see if there may be an authResult, and an accessToken and idToken. If true, we go within the authResult to the setSession technique and redirect the person to the homepage.

We’ll use setSession() to create a session for the authenticated person and retailer the authentication information in native storage in a while. If there are any errors, we use the alert technique to indicate them and in addition log the error object to the console.

We name the handleAuth() technique we outlined above within the useEffect each time Callback mounts, that’s, when the person will get redirected after logging in.

import React, {useEffect} from 'react'
const Callback = ({auth}) => {
  useEffect(() => {
  }, [])

  return (
      <h1>I'm the callback part</h1>
export default Callback

We do that as a result of when Auth0 redirects the person to the Callback part, we would like to have the ability to entry the response information it sends alongside within the redirect URL, and the handleAuth() technique is the place we name Auth0’s parseHash technique. So when the part mounts, we name handleAuth() within the useEffect.

Monitoring Authentication State

We don’t need the profile web page to be accessible if a person has not logged in. We want to have the ability to verify if the person is authenticated after which give them entry to the profile web page. We are able to make use of the setSession() technique we known as within the handleAuth() technique we’ve within the Auth class.

setSession = authResult => {
    //set the time the entry token will expire
    const expiresAt = JSON.stringify(
      authResult.expiresIn * 1000 + new Date().getTime()

    localStorage.setItem("access_token", authResult.accessToken)
    localStorage.setItem("id_token", authResult.idToken)
    localStorage.setItem("expires_at", expiresAt)

In setSession() we add an expiresAt variable to carry the time the entry token will expire. expiresIn is a string containing the expiration time (in seconds) of the accessToken. We convert the expiration time we get from expiresIn to Unix epoch time. Subsequent, we save expiresAt, and the authResult’s accessToken and idToken to native storage.

The subsequent step in establishing a tracker for the authentication state is to create an isAuthenticated technique.

isAuthenticated = () => { 
    const expiresAt =JSON.parse(localStorage.getItem("expires_at"));
    return new Date().getTime() < expiresAt;

Within the technique above, we parse the expires_at worth that we saved to native storage and verify if the present time is lower than the time the token expires. If true, then the person is authenticated.

Now that we are able to observe the isAuthenticated state, we are able to use it in our app. Let’s use it within the Nav.js file.

import React from 'react';
import { Hyperlink } from 'react-router-dom' 

const Nav = ({auth}) => {
  return (
        <li><Hyperlink to="/">Dwelling</Hyperlink></li>
          <button onClick={auth.isAuthenticated() ? auth.logout : auth.login}>
            {auth.isAuthenticated() ? "sign off" : "log in"}

export default Nav

As an alternative of hard-coding a login button and utilizing the login() technique, we dynamically render both the login button with the login() technique or the logout button with the logout() technique based mostly on the isAuthenticated state. Within the Nav part we make use of a ternary operator to find out the textual content that will get displayed on the button and the tactic that will get known as when the person clicks the button. The displayed textual content and known as technique relies on the worth of auth.isAuthenticated().

Now we are able to go forward to implement the Dwelling part.

import {Hyperlink} from 'react-router-dom'
const Dwelling = ({auth}) => {
  return (
        auth.isAuthenticated() && (
            You might be logged in! Now you can view your{' '}
            <Hyperlink to="/profile">profile</Hyperlink>
export default Dwelling

Within the Dwelling part above, we use the isAuthenticated state to dynamically show a hyperlink to the person’s profile if the person is logged in.

We wish to show details about a person after they login to the app. To do that, we’ve to create two technique within the Auth class that may get that data.

getAccessToken = () => {
    const accessToken = localStorage.getItem("access_token")
      throw new Error("No entry token discovered")
    return accessToken

The entry token is required to get the person information. We create a getAccessToken() technique that will get the entry token from native storage. If there isn’t a entry token, we throw an error.

The getProfile() technique will get the person information for us and here’s what it ought to appear to be.

getProfile = callback => {
  this.auth0.consumer.userInfo(this.getAccessToken(), (err, profile) => {

The getProfile() technique calls the userInfo() technique which can make a request to the /userinfo endpoint and return the person object, which incorporates the person data. The entry token is required for the /userinfo endpoint, so we go getAccessToken() as an argument.

The person profile data included within the response depends upon the scopes we set. Earlier on, we set the scope for our app to profile and e-mail, so these are the one items of details about the person we are going to get again.

Allow us to arrange the Profile part.

import React, { useEffect, useState } from "react";

const Profile = ({ auth }) => {
  const [profile, setProfile] = useState(null);
  useEffect(() => {
    auth.getProfile((profile) => {
  }, [auth]);

  if (!profile) {
    return <h1>Loading...</h1>;

  return (
        <img src={profile.image} />
        <pre>{JSON.stringify(profile, null, 2)}</pre>
export default Profile;

In Profile.js, we create a profile state, and within the useEffect we name the getProfile technique to entry the person’s profile. Then we show the person information we get from the profile state.

Including Logout Performance

We outline a logout() technique within the Auth class.

logout = () => {
      clientID: course of.env.REACT_APP_AUTH0_CLIENTID,
      returnTo: "http://localhost:3000"

Right here, we take away the authResult, accessToken, and idToken we beforehand saved within the native storage. Then we direct the person to the homepage.

To log a person out from Auth0’s servers, use the Auth0 logout() technique. This technique accepts an choices object that incorporates the clientID and a returnTo property. returnTo is the place you specify the URL in your app the person needs to be redirected to as soon as they logout. The returnTo URL that’s supplied should be listed within the app’s Allowed Logout URLs within the Auth0 dashboard.

Authentication Utilizing React SDK

Not like the JavaScript SDK, the React SDK is simpler to make use of. The code for this part is on the market on GitHub.

Let’s set it up in our app. The parts of this demo app are:

  • App.js: that is the basis part.
  • LoginButton.js: handles the login performance.
  • LogoutButon.js: handles the logout performance.
  • Navbar.js: this holds the logout and login buttons.
  • Profile.js: it will maintain the data of the logged-in person.

First, we set up Auth0’s React SDK in our React app.

npm set up @auth0/auth0-react

Equally to how we arrange utilizing the JavaScript SDK, we arrange the Auth0 credentials we want. We create a .env to retailer the area and cleintId credentials of your app.

import {Auth0Provider} from '@auth0/auth0-react';

const area = course of.env.REACT_APP_AUTH0_DOMAIN
const clientId = course of.env.REACT_APP_AUTH0_CLIENT_ID

    <App />

To make use of the SDK, we have to wrap our app in an Auth0Provider part. This may present the React Context to the parts which can be inside your app. We additionally set a redirectUri, which is the place Auth0 redirects the person to after they log in. Beneath the hood, the Auth0 React SDK makes use of React Context to handle the authentication state of your customers.

Setting Up Login

Right here, we arrange the login button.

import {useAuth0} from '@auth0/auth0-react';
import {Button} from './Kinds';

const LoginButton = () => {
  const {loginWithPopup} = useAuth0()
   <Button onClick={() => loginWithPopup()}>
    Log in

Auth0 supplies us two methods of establishing login in our apps. We are able to use the loginWithPopup() or loginWithRedirect() strategies. On this case, I used loginWithPopup().

We destructure loginWithPopup() from the useAuth0 hook the SDK supplies. Then we go loginWithPopup() to the button’s onClick occasion. With that, we’ve arrange the login button. If we had used loginWithRedirect(), the person can be redirected to Auth0 Login Web page. As soon as the person has been authenticated, Auth0 redirects the again to your app.

Setting Up Logout

Let’s arrange the logout performance.

import {Button} from './Kinds';
import {useAuth0} from '@auth0/auth0-react';

const LogoutButton = () => {
  const {logout} = useAuth0()
    <Button onClick={() => logout()}>
      Log Out

What we’ve right here is much like the login button setup. The one distinction is that what we pulled out from the SDK is the logout perform, and that’s what we go to the button’s onClick occasion.

Calling logout() redirects your customers to your Auth0 logout endpoint (https://YOUR_DOMAIN/v2/logout) after which instantly redirects them to the URL you specified within the Allowed Logout URLs filed of your app’s settings.

Monitoring Authentication State

We wish to conditionally render both the LogoutButton or the LoginButton based mostly on the authentication state.

import {StyledNavbar} from './Kinds';
import {useAuth0} from '@auth0/auth0-react';
import LoginButton from './LoginButton';
import LogoutButton from './LogoutButton';

const Navbar = () => {
  const {isAuthenticated} = useAuth0()
  return (
     { isAuthenticated ? <LogoutButton/> :  <LoginButton/> }  

We get isAuthenticated from useAuth0. isAuthenticated is a boolean that tells us if somebody has signed in or not. In our Navbar, we use isAuthenticated to conditionally render the buttons. We don’t have to undergo the tedious strategy of establishing a number of customized strategies simply to trace the authentication state as we did with the JavaScript SDK. The isAuthenticated boolean makes our lives simpler.

Displaying Person Information

We wish to show the person’s information as soon as they efficiently login to our app.

import {useAuth0} from '@auth0/auth0-react'
import {ProfileBox, Picture, P} from './Kinds';

const Profile = () => {
const {person, isAuthenticated} = useAuth0()
  isAuthenticated && (<ProfileBox> 
    <Picture src={person.image} alt={person.title}/>
    <P>Title: {person.title}</P>
    <P>Username: {person.nickname}</P>
    <P>Electronic mail: {person.e-mail}</P>

As soon as logged in, we’ve entry to a person object, which we are able to get from useAuth0 and making it attainable to entry details about the person from the thing. Right here, we additionally get isAuthenticated from useAuth0 as a result of we wish to solely show the information when a person is logged in.

Not like the JavaScript SDK the place we had to make use of the getAccessToken() and getProfile() strategies to entry the person’s profile, we don’t have to try this with the React SDK.

Including Social Logins

By default, Auth0 comes with Google login activated. Nevertheless, you could wish to give your person extra choices to login to your app. Let’s add Github Login to our app.

  • In your dashboard, go to the Connections tab and choose Social. There, you’ll see the connections you’ve got arrange. Click on on the Create Connection button. I’ve already enabled Github in my app, and that’s the reason you see it right here.
Social Connections settings
Social Connections settings. (Large preview)
  • Choose the Github connection. We’ll get the clientID and the clientSecret from Github and put that into the social connection settings.
Choose connection
Select connection. (Large preview)
Github connection credentials
Github connection credentials. (Large preview)
Register a new 0Auth app
Register a brand new 0Auth app. (Large preview)

For the Homepage URL and the Authorization callback URL fields, you should utilize https://localhost:3000 or no matter URL your undertaking wants.

Subsequent, go the consumer ID and Secret into the Github connection in your Auth0 account. With that, you’ve arrange Github login into your app.


On this article, we’ve seen authenticate our React apps utilizing Auth0. We additionally went by the method of establishing Github social login in our app. Have enjoyable including authentication to your React app with Auth0.

We’ve got additionally seen authenticate our app with Auth0, and the developer-experience advantages of utilizing the React SDK over the JavaScript SDK.


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