Implementing Authentication with Supabase and Next.js

Setup Supabase

Create a Supabase project and install the client library:

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

Configure Environment

NEXT_PUBLIC_SUPABASE_URL=your-project-url\nNEXT_PUBLIC_SUPABASE_ANON_KEY=your-anon-key

Create Auth Helpers

Use the @supabase/ssr package to create server-side and client-side Supabase clients with proper cookie handling.

Login Form

Create a login page with email/password and OAuth buttons (Google, GitHub).

Middleware Protection

Use Next.js middleware to protect routes and refresh auth tokens.

Row Level Security

Enable RLS on your tables and create policies that reference auth.uid() to restrict data access per user.