NextAuth Tutorial - Google & Apple Social Login

It should be easy to get social login working with your app, because these things are EVERYWHERE.

However, it’s not as easy as you would think. There are plenty of little details that are easy to miss along the way.

In this tutorial, we’ll generate a Next.JS app from scratch and configure login with Google and login with Apple.

In case you’re curious, I only figured all this out because I’m building an app called Boom Languages. You can check it out at boomlanguages.com.

Project Generation

We’ll start by generating the NextJS project. You can pop open the docs if you want to know how I figured it out, or just follow along and trust me on this one.

Run the following to generate the app:

npx create-next-app@latest pagekey-auth-example

It’s going to ask you a bunch of questions. You can answer them all with the default choice, except for one!. Be sure to not use the App Router. It doesn’t seem like NextAuth.js has particularly good support for this new router, because it’s not mentioned in any of their docs.

> TS: yes
> ESLint: yes
> Tailwind: Yes
> src: No
> App Router: No  <<<<<<<<<<<<<<<<<<<<<<<<< Very important! next-auth docs are for NOT updated for the app router
> Import alias: No

Now jump into the directory it created and start up the dev server.

cd pagekey-auth-example
npm run dev

If you visit localhost:3000 in your browser, you’ll see a fresh Next.js app waiting for you.

Creating the Buttons

Let’s create the most basic possible setup - two buttons on a page, one for Google and one for Apple.

Keep in mind that we won’t be styling the buttons in this tutorial. Google and Apple do this work for us. You can download pre-made buttons and logos from the following links:

Google branding guidelines (click “Download files” under Image Files)
Apple Button Generator / downloader

For reference, here’s what they look like in the Boom Languages app:

Boom Language social login buttons

Start by clearing out everything in styles/globals.css except for the tailwind imports. It’ll look like this when you’re done:

@tailwind base;
@tailwind components;
@tailwind utilities;

Replace pages/index.tsx with the following, a simple page with a couple of buttons:

export default function Home() {
  const handleLoginWithGoogle = () => {
    console.log('Ouch')
  };
  const handleLoginWithApple = () => {
    console.log('Ouch')
  };
  return (
    <>
      <div className="text-2xl font-bold my-4">My App</div>
      <button className="my-2 p-3 bg-blue-600 text-white font-bold rounded" onClick={() => handleLoginWithGoogle()}>Login with Google</button>
      <button className="my-2 p-3 bg-blue-600 text-white font-bold rounded" onClick={() => handleLoginWithApple()}>Login with Apple</button>
    </>
  );
}

Create components/Layout.tsx and add the following to make it look a little better:

export default function Layout({ children }: { children: React.ReactNode }) {
    return (
        <>
            <main className='flex flex-col items-center'>
                {children}
            </main>
        </>
    );
}

Next, replace the contents of _app.tsx with:

import Layout from '@/components/Layout';
import '@/styles/globals.css'
import type { AppProps } from 'next/app'

export default function App({ Component, pageProps }: AppProps) {
  return (
    <>
      <Layout>
        <Component {...pageProps} />
      </Layout>
    </>
  );
}

Adding NextAuth Package

Time to add the essential dependency: NextAuth. The docs are here, but again trust me - I’ll get us there all in one tutorial.

Run the following to install NextAuth:

npm i next-auth

Then, create pages/api/auth/[...nextauth].js and paste the following:

import NextAuth from "next-auth";
import AppleProvider from "next-auth/providers/apple";
import GoogleProvider from "next-auth/providers/google";


export const authOptions = {
  providers: [
    AppleProvider({
      clientId: process.env.APPLE_CLIENT_ID,
      clientSecret: process.env.APPLE_SECRET
    }),
    GoogleProvider({
      clientId: process.env.GOOGLE_CLIENT_ID,
      clientSecret: process.env.GOOGLE_CLIENT_SECRET,
    }),
  ],
  cookies: {
    pkceCodeVerifier: {
      name: "next-auth.pkce.code_verifier",
      options: {
        httpOnly: true,
        sameSite: "none",
        path: "/",
        secure: true,
      },
    },
  },
  callbacks: {
    session: async ({ session }) => {
      session.customValue = new Date().toISOString();
      return Promise.resolve(session);
    },
  },
}
export default NextAuth(authOptions)

Create the .env-sample file to let anyone who clones this repo know which environment variables our app is expecting to use:

APPLE_CLIENT_ID=
APPLE_SECRET=
GOOGLE_CLIENT_ID=
GOOGLE_CLIENT_SECRET=

And then copy that file into the real .env file:

cp .env-sample .env

Be sure to add .env to .gitignore - it will contain credentials that we don’t want to commit to Git!

echo .env >> .gitignore

Okay, here’s where it gets fun. We actually need to register our app with Google now. In exchange, they’ll give us the OAuth credentials that NextAuth needs to work.

For this part, if you get stuck, consider checking out the video that accompanies this article, which can be found at the top of the page.

The steps are roughly as follow:

Go to https://console.cloud.google.com/. Login with whatever Google account you want to use to manage your app. Agree to the Terms of Service if prompted.
Click Create Project.
Give it a name. In our case: PageKey Auth Example
Leave organization blank for now. Click Create.
Go to APIs & Services.
Go to Credentials.
Click Configure Consent Screen.
Click Create Credentials > OAuth Client ID.
Click configure consent screen
Click External, then click Create.
For App name, enter something like: PageKey Auth Example
Choose a logo file for your app.

Enter a homepage, privacy policy, and terms of service links. Example:

https://pagekey.io
https://pagekey.io/privacy
https://pagekey.io/tos

Add an authorized domain for your site. In our case: pagekey.io
Add your email for developer contact info.
Save and continue.
Click “Add or remove scopes.”
Add the following scopes:
- .../auth/userinfo.email
- .../auth/userinfo.profile
Click Save and Continue.
Add your email to the list of test users.
Go back to the dashboard.
Click Credentials.
Click Create Credentials > OAuth Client ID.
For App type, choose Web application.
Enter a name. For example: PageKey Auth Example (Web)
For Authorized JavaScript origins, enter the following, replacing pagekey.io with your domain:
```
http://localhost:3000
https://pagekey.io (put your domain here)
```

For Authorized redirect URIs, enter the following, replacing pagekey.io with your domain:

http://localhost:3000/api/auth/callback/google
https://pagekey.io/api/auth/callback/google

Click Create
Copy the Client ID and paste it into .env as the value for GOOGLE_CLIENT_ID.
Copy the Client secret and paste it into .env as the value for GOOGLE_CLIENT_SECRET.

Let’s make sure this thing is working. We just need to update our Google button handler:

import { signIn } from 'next-auth/react';

const handleLoginWithGoogle = () => {
  signIn("google");
};

Then, we’ll reconfigure the logic a bit:

  import { signIn, signOut, useSession } from 'next-auth/react';
  const { data: session } = useSession();

  ...

  let loginElem = (
    <>
      <button className="m-4p-3 bg-blue-600 text-white font-bold rounded" onClick={() => handleLoginWithGoogle()}>Login with Google</button>
      <button className="m-4 p-3 bg-blue-600 text-white font-bold rounded" onClick={() => handleLoginWithApple()}>Login with Apple</button>
    </>
  );

  if (session && session.user) {
    loginElem = (
      <div>
        <div>
          Logged in as {session.user.email}
        </div>
        <button onClick={() => signOut()}>Logout</button>
      </div>
    );
  }

  return (
    <>
      <div className="text-2xl font-bold my-4">My App</div>
      {loginElem}
    </>
  );

Oops! Looks like we need a SessionProvider

SessionProvider error

This is a quick fix. We’ll just update _app.tsx like this:

import { SessionProvider } from 'next-auth/react';
...
      <SessionProvider>
        <Layout>
          <Component {...pageProps} />
        </Layout>
      </SessionProvider>
...

Now try logging in with Google.

It should work!

Working Login

Of course this is going to be a pain.

Login to developer.apple.com
Go to Account
Click Identifiers
In the top right, click App IDs and change it to Services IDs. (Ridiculously tricky step)

Tricky step

Click the plus to register a new Services ID.
Click continue. Ad a description and identifier.

Registering services id

Click your new service id.
Click “Enabled’ next to “Sign in with Apple”.
Click “Configure”
Select your primary app id - assumption is that you have already created this elsewhere
For domains, put your web domain - boom.pagekey.io for me.
In return URLs, put something like https://boom.pagekey.io/api/auth/callback/apple. Replace boom.pagekey.io with the domain where you’ll host your app.
Click Done.

Generating the Key, Getting the Secret

Now we have to get the APPLE_CLIENT_ID and APPLE_SECRET environment variables. Unfortunately, Apple makes this pretty complicated. We’ll start by generating a key.

Go to Keys on Apple Developer.
Click the plus to create a new key. Give it a name. Click Sign in with Apple. Click Configure. Select your app from the list. Click Save. Click Continue. Click Register.
Note the Key ID - copy it into a note, you’ll need it later. Then press Download.

Open the private key file that just downloaded in a text editor. It should look something like this:

Paste the key into your terminal like this:

export APPLE_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----
MIGTAgEAMBMGByqGSM49tgEGCCqGSM49AwEHBHkwdSIBAQQg6XgE1Gh6AOA6ShuR
Pomi8sUETCJ7jxBL154Ud+a2OgCgYIKoZIzj0DArehRANCAARF4FKAbPdpTvR5
Q5fGoR2tKBYmV4HX/uOkPVu3CIL4lwKaAqOqop5FQ3I4lV7JKQ0tgAytx8JKn9NL
NgQlPaby
-----END PRIVATE KEY-----"

Note: If you have problems with this, you can also try replacing all line breaks with \\n and see if that helps.

Look in the top right corner of Apple Developer to locate your Team ID.

Copy this script into the scripts folder of your project and run it like this:

chmod +x ./scripts/apple-gen-secret.mjs
export APPLE_KEY_ID=paste-your-key-id-from-above
export APPLE_TEAM_ID=paste-your-team-id
export APPLE_CLIENT_ID=io.pagekey.boom # replace with your domain
# note that APPLE_PRIVATE_KEY has already been set above
./scripts/apple-gen-secret.mjs --kid $APPLE_KEY_ID --iss $APPLE_TEAM_ID --private_key $APPLE_PRIVATE_KEY --client-id $APPLE_CLIENT_ID

It should generate something like this:

Apple client secret generated. Valid until: Thu Feb 15 2024 07:51:54 GMT-0500 (Eastern Standard Time)
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IlBsZWFzZSBkb24ndCBoYWNrIG1lIDopIiwiaWF0IjoxNTE2MjM5MDIyfQ.yNMm_loH6ybgHaRkKlPlbPf6pPoYH3ajvDLpBjUdYNk

Copy that entire token starting with ey. Now we have all the data we need to fill out our .env file!

APPLE_CLIENT_ID=io.pagekey.boom # replace with your domain
APPLE_SECRET=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IlBsZWFzZSBkb24ndCBoYWNrIG1lIDopIiwiaWF0IjoxNTE2MjM5MDIyfQ.yNMm_loH6ybgHaRkKlPlbPf6pPoYH3ajvDLpBjUdYNk

That’s pretty much all we need to do for Apple login.

There are fancy ways to test this using localhost, but I didn’t bother because I find Apple really annoying. I don’t want to generate certs, etc. So I just deploy and test on my production app. Try it out at boomlanguages.com to see it in action.

Conclusion

Thanks for following along. If you enjoyed this post, consider signing up for the PageKey mailing list to stay up-to-date with all the latest happenings of PageKey.

NextAuth Tutorial - Google & Apple Social Login

Project Generation

Creating the Buttons

Adding NextAuth Package

Generating the Key, Getting the Secret

Conclusion

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Project Generation

Creating the Buttons

Adding NextAuth Package

Configuring Login with Google

Testing Login with Google

Configuring Login with Apple

Generating the Key, Getting the Secret

Conclusion

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21 Programming Terms for Absolute Beginners

How to Make a Python Package / Upload to PyPi

OS8: Calling C from Assembly

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