Supabase Row Level Security Policies: Examples & Patterns
Copy-paste Supabase RLS policy examples: auth.uid() CRUD patterns, USING vs WITH CHECK, public read access, and Flutter wiring.
These supabase row level security policies examples are the ones I copy into every new project: the CRUD set that lets users touch only their own rows, the public-read pattern, and the security-definer trick for anything fancier. Row Level Security is Postgres doing your authorization for you — every query from your Flutter app automatically carries the signed-in user's identity, and the database itself decides which rows they may see. Get it right and you delete a whole class of "user A saw user B's data" bugs; get it wrong and your app either leaks data or mysteriously reads nothing at all. Last updated: October 3, 2026 What you'll learn What RLS is and why you enable it on every table The complete CRUD policy set: SELECT, INSERT, UPDATE, DELETE The auth.uid() = user_id pattern for per-user data USING vs WITH CHECK — which one, where, and why Public-read and authenticated-only patterns Security definer functions for roles and membership checks How RLS works from the Flutter client Supabase Row Level Security Policies Examples: The Mental Model Before the SQL, the mental model — because most RLS confusion is conceptual, not syntactic: RLS is a row filter, not a login wall. When enabled, Postgres silently appends your policy conditions to every query. Your Flutter code stays the same; the database returns fewer rows. auth.uid() is the signed-in user's id , extracted from their JWT. In policies you compare it against a user_id (or id ) column. Policies are additive and permissive. If *any* policy allows the operation, it's allowed. There's no "deny" policy — you restrict by writing narrow conditions. RLS enabled + zero policies = zero rows. This is the most common "my query returns nothing" bug. Enabling RLS without policies locks everyone…