Supabase Security and Row Level Security Best Practices
Row Level Security (RLS) in Supabase means protection rules run inside the database itself, regardless of how a request reaches it.
core keys: anon key (subject to RLS) and service role key (bypasses it)
step never to delay: enabling RLS immediately on a new table
actual protection for a table without a clear RLS policy
Row Level Security (RLS) lets you write policies defining who can read or modify each row in a table, and these policies are enforced inside the database itself, regardless of how a request reaches it.
The Difference Between anon key and service role key
The anon key is meant for client code and is fully subject to RLS policies, while the service role key bypasses RLS entirely and has full privileges — so it must stay server-side only, never in code reachable by the browser.
A Common Mistake to Avoid
Creating a new table without enabling RLS on it immediately, assuming "adding it later" is fine — any table without RLS enabled and a clear policy is fully open to any request using the anon key if no restrictive policies are defined.
Questions & Answers
01Is enabling RLS alone enough without policies?
No, enabling RLS with no policy blocks all access via the anon key entirely; you must write clear policies defining what access is actually allowed.
02When is it safe to use the service role key?
Only in fully trusted server-side code (like API routes or admin scripts), and never in any code reachable by the browser or exposed in the client bundle.
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