Why RLS Is the Core of Any Paywall The scariest scenario for a paid content service: Someone who hasn't paid can see your content. If you control access with if (purchased) { showContent() } on the client side, an attacker can bypass it by disabling JavaScript or hitting your API directly. Even if you check on the server, accidentally exposing an API that fetches all users' purchase history will sink you. Supabase Row Level Security (RLS) solves this at the database layer. The database itself decides "this user can/cannot see this row" — so application-level bugs can't bypass it. I use RLS on this blog's paid articles. Even if there's a bug in the Next.js access control logic, the database layer blocks it. Defense in depth. What you'll learn: RLS concepts and 2-layer defense design RLS policy design for purchase history tables When to use Service Role Key vs.…