Supabase Auth SSR Setup

Overview

Configure Supabase Authentication for Next.js App Router with server-side rendering (SSR), secure cookie-based sessions, middleware protection, and complete authentication flows.

Installation and Configuration Steps

1. Install Dependencies

Install Supabase SSR package for Next.js:

npm install @supabase/supabase-js @supabase/ssr

2. Create Supabase Client Utilities

Create three client configurations for different contexts (browser, server, middleware):

File: lib/supabase/client.ts (Browser client)

Use the template from assets/supabase-client.ts. This client:

• Runs only in browser context
• Uses secure cookies for session storage
• Automatically refreshes tokens

File: lib/supabase/server.ts (Server component client)

Use the template from assets/supabase-server.ts. This client:

• Creates server-side Supabase client with cookie access
• Used in Server Components and Server Actions
• Provides read-only cookie access for security

File: lib/supabase/middleware.ts (Middleware client)

Use the template from assets/supabase-middleware.ts. This client:

• Used in Next.js middleware for route protection
• Can update cookies in responses
• Refreshes sessions on route navigation

3. Configure Environment Variables

Add Supabase credentials to .env.local:

NEXT_PUBLIC_SUPABASE_URL=your-project-url
NEXT_PUBLIC_SUPABASE_ANON_KEY=your-anon-key

Get these values from your Supabase project settings under API.

Security note: The anon key is safe to expose publicly. Real security comes from Row Level Security (RLS) policies in your database.

4. Create Middleware for Route Protection

Create middleware.ts in project root using the template from assets/middleware.ts. This middleware:

• Refreshes Supabase session on every request
• Protects routes matching specified patterns
• Redirects unauthenticated users to login
• Allows public routes to bypass authentication

Configure protected routes by adjusting the matcher pattern:

export const config = {
  matcher: [
    '/dashboard/:path*',
    '/settings/:path*',
    '/api/protected/:path*',
  ],
};

5. Create Authentication Utilities

Create helper functions for common auth operations using templates from assets/auth-utils.ts:

Get current user server-side:

import { getCurrentUser } from '@/lib/auth/utils';

const user = await getCurrentUser();

Require authentication:

import { requireAuth } from '@/lib/auth/utils';

const user = await requireAuth(); // Throws error if not authenticated

Get session:

import { getSession } from '@/lib/auth/utils';

const session = await getSession();

These utilities simplify authentication checks in Server Components and Server Actions.

6. Create Logout Server Action

Create app/actions/auth.ts using the template from assets/auth-actions.ts. This provides:

Logout action:

• Clears Supabase session
• Removes auth cookies
• Redirects to home page

Use in client components:

import { logout } from '@/app/actions/auth';

<button onClick={() => logout()}>
  Sign Out
</button>

7. Create Login Page

Create app/login/page.tsx using the template from assets/login-page.tsx. This page:

• Provides email/password login form
• Handles magic link authentication
• Supports OAuth providers (Google, GitHub, etc.)
• Redirects authenticated users
• Shows error messages

Customize the login page:

• Add your branding and styling
• Enable/disable OAuth providers
• Add password reset link
• Include sign-up link

8. Create Protected Route Example

Create a protected dashboard page at app/dashboard/page.tsx using the template from assets/dashboard-page.tsx. This demonstrates:

• Using requireAuth() to protect routes
• Displaying user information
• Including logout functionality
• Server-side authentication check

9. Set Up Callback Route for OAuth

If using OAuth providers, create app/auth/callback/route.ts using the template from assets/auth-callback-route.ts. This handler:

• Exchanges OAuth code for session
• Sets secure session cookies
• Redirects to intended destination
• Handles OAuth errors

Configure OAuth in Supabase dashboard:

1. Go to Authentication > Providers
2. Enable desired providers (Google, GitHub, etc.)
3. Add redirect URL: https://your-domain.com/auth/callback

Authentication Flow

Login Flow

1. User visits /login
2. User enters credentials or clicks OAuth
3. Supabase authenticates and sets session cookie
4. User redirected to dashboard or intended page
5. Middleware validates session on protected routes

Session Refresh Flow

1. User navigates to any route
2. Middleware runs and refreshes session if needed
3. Updated session cookie sent to client
4. Server Components have access to fresh session

Logout Flow

1. User clicks logout button
2. Server Action calls Supabase signOut()
3. Session and cookies cleared
4. User redirected to home page

Route Protection Patterns

Protecting Individual Pages

Use requireAuth() at the top of Server Components:

import { requireAuth } from '@/lib/auth/utils';

export default async function ProtectedPage() {
  const user = await requireAuth();

  return <div>Hello {user.email}</div>;
}

Protecting Route Groups

Use Next.js route groups with layout:

// app/(protected)/layout.tsx
import { requireAuth } from '@/lib/auth/utils';

export default async function ProtectedLayout({ children }) {
  await requireAuth();
  return <>{children}</>;
}

All routes in (protected) group are automatically protected.

Optional Authentication

Check if user is logged in without requiring it:

import { getCurrentUser } from '@/lib/auth/utils';

export default async function OptionalAuthPage() {
  const user = await getCurrentUser();

  return (
    <div>
      {user ? `Welcome ${user.email}` : 'Please log in'}
    </div>
  );
}

Server Actions with Authentication

Protect Server Actions using requireAuth():

'use server';

import { requireAuth } from '@/lib/auth/utils';
import { createServerClient } from '@/lib/supabase/server';

export async function updateProfile(formData: FormData) {
  const user = await requireAuth();
  const supabase = createServerClient();

  const { error } = await supabase
    .from('profiles')
    .update({ name: formData.get('name') })
    .eq('id', user.id);

  if (error) throw error;
}

Troubleshooting

Session not persisting: Verify cookies are being set. Check browser dev tools > Application > Cookies. Ensure domain matches.

Middleware redirect loop: Check matcher pattern doesn't include login page. Verify /login is accessible without auth.

OAuth redirect fails: Confirm callback URL matches exactly in Supabase dashboard. Check for trailing slashes.

TypeScript errors: Install types: npm install -D @types/node. Ensure supabase is typed correctly.

401 errors on protected routes: Session may be expired. Check Supabase dashboard > Authentication > Settings for session timeout.

Resources

scripts/

No executable scripts needed for this skill.

references/

• authentication-patterns.md - Common auth patterns and best practices for Next.js + Supabase
• security-considerations.md - Security best practices for session handling and cookie configuration

assets/

• supabase-client.ts - Browser-side Supabase client configuration
• supabase-server.ts - Server-side Supabase client for Server Components
• supabase-middleware.ts - Middleware Supabase client for session refresh
• middleware.ts - Next.js middleware for route protection
• auth-utils.ts - Helper functions for authentication checks
• auth-actions.ts - Server Actions for logout and other auth operations
• login-page.tsx - Complete login page with email/password and OAuth
• dashboard-page.tsx - Example protected page using requireAuth
• auth-callback-route.ts - OAuth callback handler for provider authentication