Setting up Server-Side Auth for Next.js

Next.js comes in two flavors: the App Router and the Pages Router. You can set up Server-Side Auth with either strategy. You can even use both in the same application.

Install Supabase packages

Install the @supabase/supabase-js package and the helper @supabase/ssr package.


_10npm install @supabase/supabase-js @supabase/ssr

Set up environment variables

Create a .env.local file in your project root directory.

Fill in your NEXT_PUBLIC_SUPABASE_URL and NEXT_PUBLIC_SUPABASE_ANON_KEY:

Project URL

Anon key

.env.local


_10NEXT_PUBLIC_SUPABASE_URL=<your_supabase_project_url>
_10NEXT_PUBLIC_SUPABASE_ANON_KEY=<your_supabase_anon_key>

Write utility functions to create Supabase clients

To access Supabase from your Next.js app, you need 2 types of Supabase clients:

Client Component client - To access Supabase from Client Components, which run in the browser.
Server Component client - To access Supabase from Server Components, Server Actions, and Route Handlers, which run only on the server.

Create a utils/supabase folder with a file for each type of client. Then copy the utility functions for each client type.

utils/supabase/client.ts

utils/supabase/server.ts


_10import { createBrowserClient } from '@supabase/ssr'
_10
_10export function createClient() {
_10  return createBrowserClient(
_10    process.env.NEXT_PUBLIC_SUPABASE_URL!,
_10    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!
_10  )
_10}

Hook up middleware

Create a middleware.ts file at the root of your project.

Since Server Components can't write cookies, you need middleware to refresh expired Auth tokens and store them.

The middleware is responsible for:

Refreshing the Auth token (by calling supabase.auth.getUser).
Passing the refreshed Auth token to Server Components, so they don't attempt to refresh the same token themselves. This is accomplished with request.cookies.set.
Passing the refreshed Auth token to the browser, so it replaces the old token. This is accomplished with response.cookies.set.

Copy the middleware code for your app.

Add a matcher so the middleware doesn't run on routes that don't access Supabase.

Be careful when protecting pages. The server gets the user session from the cookies, which can be spoofed by anyone.

Always use supabase.auth.getUser() to protect pages and user data.

Never trust supabase.auth.getSession() inside server code such as middleware. It isn't guaranteed to revalidate the Auth token.

It's safe to trust getUser() because it sends a request to the Supabase Auth server every time to revalidate the Auth token.

middleware.ts

utils/supabase/middleware.ts


_19import { type NextRequest } from 'next/server'
_19import { updateSession } from '@/utils/supabase/middleware'
_19
_19export async function middleware(request: NextRequest) {
_19  return await updateSession(request)
_19}
_19
_19export const config = {
_19  matcher: [
_19    /*
_19     * Match all request paths except for the ones starting with:
_19     * - _next/static (static files)
_19     * - _next/image (image optimization files)
_19     * - favicon.ico (favicon file)
_19     * Feel free to modify this pattern to include more paths.
_19     */
_19    '/((?!_next/static|_next/image|favicon.ico|.*\\.(?:svg|png|jpg|jpeg|gif|webp)$).*)',
_19  ],
_19}

Create a login page

Create a login page for your app. Use a Server Action to call the Supabase signup function.

Since Supabase is being called from an Action, use the client defined in @/utils/supabase/server.ts.

Note that cookies is called before any calls to Supabase, which opts fetch calls out of Next.js's caching. This is important for authenticated data fetches, to ensure that users get access only to their own data.

See the Next.js docs to learn more about opting out of data caching.

app/login/page.tsx

app/login/actions.ts

app/error/page.tsx


_14import { login, signup } from './actions'
_14
_14export default function LoginPage() {
_14  return (
_14    <form>
_14      <label htmlFor="email">Email:</label>
_14      <input id="email" name="email" type="email" required />
_14      <label htmlFor="password">Password:</label>
_14      <input id="password" name="password" type="password" required />
_14      <button formAction={login}>Log in</button>
_14      <button formAction={signup}>Sign up</button>
_14    </form>
_14  )
_14}

Change the Auth confirmation path

If you have email confirmation turned on (the default), a new user will receive an email confirmation after signing up.

Change the email template to support a server-side authentication flow.

Go to the Auth templates page in your dashboard. In the Confirm signup template, change {{ .ConfirmationURL }} to {{ .SiteURL }}/auth/confirm?token_hash={{ .TokenHash }}&type=signup.

Create a route handler for Auth confirmation

Create a Route Handler for auth/confirm. When a user clicks their confirmation email link, exchange their secure code for an Auth token.

Since this is a Router Handler, use the Supabase client from @/utils/supabase/server.ts.

app/auth/confirm/route.ts


_33import { type EmailOtpType } from '@supabase/supabase-js'
_33import { type NextRequest, NextResponse } from 'next/server'
_33
_33import { createClient } from '@/utils/supabase/server'
_33
_33export async function GET(request: NextRequest) {
_33  const { searchParams } = new URL(request.url)
_33  const token_hash = searchParams.get('token_hash')
_33  const type = searchParams.get('type') as EmailOtpType | null
_33  const next = searchParams.get('next') ?? '/'
_33
_33  const redirectTo = request.nextUrl.clone()
_33  redirectTo.pathname = next
_33  redirectTo.searchParams.delete('token_hash')
_33  redirectTo.searchParams.delete('type')
_33
_33  if (token_hash && type) {
_33    const supabase = createClient()
_33
_33    const { error } = await supabase.auth.verifyOtp({
_33      type,
_33      token_hash,
_33    })
_33    if (!error) {
_33      redirectTo.searchParams.delete('next')
_33      return NextResponse.redirect(redirectTo)
_33    }
_33  }
_33
_33  // return the user to an error page with some instructions
_33  redirectTo.pathname = '/error'
_33  return NextResponse.redirect(redirectTo)
_33}

Access user info from Server Component

Server Components can read cookies, so you can get the Auth status and user info.

Since you're calling Supabase from a Server Component, use the client created in @/utils/supabase/server.ts.

Create a private page that users can only access if they're logged in. The page displays their email.

Be careful when protecting pages. The server gets the user session from the cookies, which can be spoofed by anyone.

Always use supabase.auth.getUser() to protect pages and user data.

Never trust supabase.auth.getSession() inside Server Components. It isn't guaranteed to revalidate the Auth token.

It's safe to trust getUser() because it sends a request to the Supabase Auth server every time to revalidate the Auth token.

app/private/page.tsx


_14import { redirect } from 'next/navigation'
_14
_14import { createClient } from '@/utils/supabase/server'
_14
_14export default async function PrivatePage() {
_14  const supabase = createClient()
_14
_14  const { data, error } = await supabase.auth.getUser()
_14  if (error || !data?.user) {
_14    redirect('/login')
_14  }
_14
_14  return <p>Hello {data.user.email}</p>
_14}

Congratulations

You're done! To recap, you've successfully:

Called Supabase from a Server Action.
Called Supabase from a Server Component.
Set up a Supabase client utility to call Supabase from a Client Component. You can use this if you need to call Supabase from a Client Component, for example to set up a realtime subscription.
Set up middleware to automatically refresh the Supabase Auth session.

You can now use any Supabase features from your client or server code!

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