Why Supabase RLS Errors Are a Feature, Not a Bug — And How to Fix Them

Developers using Supabase often encounter the error 'new row violates row-level security policy,' which signals that Row-Level Security (RLS) is active and correctly blocking unauthorized writes by default. The error typically stems from one of three causes: a missing INSERT policy, a mismatched or null user_id field, or an unauthenticated request where auth.uid() returns null. The recommended fix involves creating an explicit INSERT policy that allows signed-in users to write only their own rows, combined with a server-side column default to automatically assign the correct user ID. Developers are also cautioned that the Supabase SQL editor runs with elevated privileges that bypass RLS, meaning successful writes there do not guarantee the same behavior from a client app. Disabling RLS to silence the error is discouraged, as an unprotected table is the more serious security risk.