"Supabase 42501 Permission Denied Fix: Flutter Guide"
Supabase 42501 permission denied fix for Flutter: missing GRANTs, RLS without policies, and the Oct 2026 auto-grant removal — with copy-paste SQL fixes.
permission denied for table users — error code 42501 . Your Flutter app was working yesterday, the query looks right, the table exists, and yet Supabase slaps your hand. The Supabase 42501 permission denied fix is almost always one of three things: RLS enabled with no policies, missing GRANTs to the anon / authenticated roles, or — the new one catching everyone in late 2026 — Supabase no longer auto-grants privileges on new tables. This guide diagnoses which cause is yours and gives you the exact SQL to fix it. Every snippet is copy-paste ready for the Supabase SQL editor. *Last updated: October 3, 2026* What you'll learn What error 42501 actually means (and how PostgREST disguises it as 401/403) The three root causes: RLS without policies, missing GRANTs, the October 2026 auto-grant removal Copy-paste SQL fixes for schemas, tables, sequences, and RPC functions How to check which role your Flutter app is actually using Why service_role can still get 42501 The GRANT ALL trap to avoid What Error 42501 Actually Means 42501 is the Postgres code for insufficient_privilege . When your Flutter app queries through PostgREST (which is what supabase_flutter does), the request runs as a Postgres role — anon for logged-out users, authenticated for logged-in users. Postgres checks two independent layers before returning rows: GRANTs — does this role have permission to touch the schema/table at all? RLS policies — if row-level security is enabled, does a policy allow these specific rows? Both must pass. A perfect RLS policy means nothing if the role was never granted SELECT . And generous GRANTs mean nothing if RLS is enabled with zero policies (Postgres denies everything by default). One more wrinkle: PostgREST often surfaces 42501 to your Flutter app as HTTP 401 or 403 , and…