Row-Level Security in Enterprise Data with Supabase
Moving authorization from client code to the database: Key principles to consider when designing Row Level Security policies.
One of the most common mistakes in enterprise applications is performing authorization checks solely in the UI. It is often assumed that when a button is hidden, the data is also protected; however, for someone making direct API requests, that button never existed in the first place.
Authorization must live in the database
PostgreSQL's Row Level Security feature allows you to define policy conditions that are automatically appended to every query. Supabase combines these policies with authentication data: it recognizes the current user via auth.uid() and returns only the permitted rows.
Do not trust data that users can modify
While it is tempting to store role information in user metadata, this field can often be updated by the client. A more secure approach is to keep roles in separate tables and check them using security definer functions.
Checklist
- Enable RLS on every table and deny everything by default.
- Limit anonymous read policies to published content only.
- Tie write operations to authorization tables.
- Verify policies with automated tests.
This approach forms the foundation of the administration panels we develop at Cy Logic.