Let's integrate auth.js with Supabase!

Hello everyone, Recently I was building a chat app. It was very quick to build a real-time app with supabase. I was amazed. I used this tech stack:

Next.js
Auth.js (next-auth)
Supabase

I am not going to cover full project in this post feel free to comment for that. For now We are going to setup authentication with auth.js and supabase. So, Let's begain.

Step 1: Create a next.js project.

There are many ways to create next.js project. I am going to use Bun. It is faster then alternatives as of now 😊.

bun create next-app supa-auth

create a project by this command replace supa-auth with your project name. It will ask several questions chose as per your choice. I will use typescript.

You can open this project in any code editor you want I am using Vscode.

Step 2: Create a Supabase Project.

Navigate to Supabase Website. Create an account and create a new project.

Create Supabase project form

fill project name, password, select the region that is close to you and create project. Now you will be redirected to this screen:

Supabase project dashboard

Copy Project URL and API Key go to your project directory create a .env file and this fields:

NEXT_PUBLIC_SUPABASE_URL= <your project url>
SUPABASE_ANON_KEY= <your project api key>

Step 3: Setup auth.js with simple UI.

Let's install dependencies for auth.js

bun add next-auth@beta @supabase/supabase-js @auth/supabase-adapter

These are the dependencies you need to install to setup supabase with auth.js.

After installation Setup auth.js Create a auth.ts file in root of your project (if you selected src folder during installation then create file inside src).

This file will look like this:

import { SupabaseAdapter } from "@auth/supabase-adapter";
import NextAuth from "next-auth";
import Google from "next-auth/providers/google";
 
export const { handlers, signIn, signOut, auth } = NextAuth({
  providers: [Google],
  adapter: SupabaseAdapter({
    url: process.env.NEXT_PUBLIC_SUPABASE_URL as string,
    secret: process.env.SUPABASE_ANON_KEY as string,
  }),
  debug: process.env.NODE_ENV === "development",
  session: { strategy: "jwt" },
});

You can tweak this file as per your requirement. I am going to use Google Oauth to signin you can use others also. you can see from auth.js docs.

Add Google Client ID and Secret in .env file and add auth secret for auth.js like this:

NEXT_PUBLIC_SUPABASE_URL= <your project url>
SUPABASE_ANON_KEY= <your project api key>

AUTH_SECRET="secret-for-authjs" # change this

AUTH_GOOGLE_ID= <your google client id>
AUTH_GOOGLE_SECRET= <your google client secret>

Remember to write variable name as given for AUTH_GOOGLE_ID, AUTH_GOOGLE_SECRET and AUTH_SECRET. It is required see more

You will get Google client id and secret from Google Cloud Console.

Add this to Authorised redirect URIs: https://localhost:3000/api/auth/callback/google

Now create a middlware.ts file in root of your project beside auth.ts.

export { auth as middleware } from "@/auth"
 
export const config = {
  matcher: ["/((?!.+\\.[\\w]+$|_next).*)", "/(api|trpc)(.*)"],
};

Finally Add a Route Handler under /app/api/auth/[...nextauth]/route.ts. Add this to the file:

import { handlers } from "@/auth" // Referring to the auth.ts we just created
export const { GET, POST } = handlers

Step 4: Now create a signin Button component.

create a file /components/sign-in.tsx. with this content:

 
import { signIn } from "@/auth"
 
export function SignIn() {
  return (
    <form
      action={async () => {
        "use server"
        await signIn("google")
      }}
    >
      <button type="submit">Signin with Google</button>
    </form>
  )
}

Now Just add this component to make user signin by clicking on this button.

Step 5: Bind Supabase db with auth.js (Important)

This part is very important and crucial. So, Please give it time.

Go to your supabase project. Click on SQL Editor looks like this:

Supabase SQL Editor

Paste this into editor and run (learn more):

--
-- Name: next_auth; Type: SCHEMA;
--
CREATE SCHEMA next_auth;
 
GRANT USAGE ON SCHEMA next_auth TO service_role;
GRANT ALL ON SCHEMA next_auth TO postgres;
 
--
-- Create users table
--
CREATE TABLE IF NOT EXISTS next_auth.users
(
    id uuid NOT NULL DEFAULT uuid_generate_v4(),
    name text,
    email text,
    "emailVerified" timestamp with time zone,
    image text,
    CONSTRAINT users_pkey PRIMARY KEY (id),
    CONSTRAINT email_unique UNIQUE (email)
);
 
GRANT ALL ON TABLE next_auth.users TO postgres;
GRANT ALL ON TABLE next_auth.users TO service_role;
 
--- uid() function to be used in RLS policies
CREATE FUNCTION next_auth.uid() RETURNS uuid
    LANGUAGE sql STABLE
    AS $$
  select
  	coalesce(
		nullif(current_setting('request.jwt.claim.sub', true), ''),
		(nullif(current_setting('request.jwt.claims', true), '')::jsonb ->> 'sub')
	)::uuid
$$;
 
--
-- Create sessions table
--
CREATE TABLE IF NOT EXISTS  next_auth.sessions
(
    id uuid NOT NULL DEFAULT uuid_generate_v4(),
    expires timestamp with time zone NOT NULL,
    "sessionToken" text NOT NULL,
    "userId" uuid,
    CONSTRAINT sessions_pkey PRIMARY KEY (id),
    CONSTRAINT sessionToken_unique UNIQUE ("sessionToken"),
    CONSTRAINT "sessions_userId_fkey" FOREIGN KEY ("userId")
        REFERENCES  next_auth.users (id) MATCH SIMPLE
        ON UPDATE NO ACTION
        ON DELETE CASCADE
);
 
GRANT ALL ON TABLE next_auth.sessions TO postgres;
GRANT ALL ON TABLE next_auth.sessions TO service_role;
 
--
-- Create accounts table
--
CREATE TABLE IF NOT EXISTS  next_auth.accounts
(
    id uuid NOT NULL DEFAULT uuid_generate_v4(),
    type text NOT NULL,
    provider text NOT NULL,
    "providerAccountId" text NOT NULL,
    refresh_token text,
    access_token text,
    expires_at bigint,
    token_type text,
    scope text,
    id_token text,
    session_state text,
    oauth_token_secret text,
    oauth_token text,
    "userId" uuid,
    CONSTRAINT accounts_pkey PRIMARY KEY (id),
    CONSTRAINT provider_unique UNIQUE (provider, "providerAccountId"),
    CONSTRAINT "accounts_userId_fkey" FOREIGN KEY ("userId")
        REFERENCES  next_auth.users (id) MATCH SIMPLE
        ON UPDATE NO ACTION
        ON DELETE CASCADE
);
 
GRANT ALL ON TABLE next_auth.accounts TO postgres;
GRANT ALL ON TABLE next_auth.accounts TO service_role;
 
--
-- Create verification_tokens table
--
CREATE TABLE IF NOT EXISTS  next_auth.verification_tokens
(
    identifier text,
    token text,
    expires timestamp with time zone NOT NULL,
    CONSTRAINT verification_tokens_pkey PRIMARY KEY (token),
    CONSTRAINT token_unique UNIQUE (token),
    CONSTRAINT token_identifier_unique UNIQUE (token, identifier)
);
 
GRANT ALL ON TABLE next_auth.verification_tokens TO postgres;
GRANT ALL ON TABLE next_auth.verification_tokens TO service_role;

After successfully execution go to your project settings inside Configuration click on API and scroll to Data API Settings looks like this:

Supabase Data API Settings

In Exposed schemas add next-auth like this:

Exposed schemas Data API Settings

Save settings.

Step 5: Run Project Now you can run your next.js project with

bun dev

Now visit https://localhost:3000 it will redirect you to https://localhost:3000/api/auth/signin. You can signin with Google.

Further you can add Auth Page to override this default page by editing auth.ts:

import { SupabaseAdapter } from "@auth/supabase-adapter";
import NextAuth from "next-auth";
import Google from "next-auth/providers/google";
 
export const { handlers, signIn, signOut, auth } = NextAuth({
  providers: [Google],
  adapter: SupabaseAdapter({
    url: process.env.NEXT_PUBLIC_SUPABASE_URL as string,
    secret: process.env.SUPABASE_ANON_KEY as string,
  }),
  debug: process.env.NODE_ENV === "development",
  session: { strategy: "jwt" },
  pages: {
    signIn: "/<sigin-page-url>",
  },
});

replace <sigin-page-url> with your auth page.

These were the easiest steps to setup supabase with auth.js. now you need to just call:

 const session = await auth()

To get user session don't need to create you own context and hooks.👍 For more information read official auth.js Docs

Thanks for your time. Priyanshu Verma