Supabase API errorSupabase: “permission denied for table” (42501)

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Why the role is denied, and the fix

1. 01

   The table has no grant for the API roles

   “A table isn't reachable through the Data API unless you have granted a role privileges on it.” Supabase, Securing your API

   Tables made with Automatically expose new tables turned off, or after a revoke in SQL, have no privileges for anon or authenticated. The error’s hint names the exact grant statement. Check, then grant.

   -- what anon and authenticated may do now
   select grantee, privilege_type
   from information_schema.role_table_grants
   where table_schema = 'public' and table_name = 'your_table'
     and grantee in ('anon', 'authenticated');
   
   -- RLS and a policy first (example policy), then the grant
   alter table public.your_table enable row level security;
   create policy "own rows" on public.your_table for select to authenticated
     using (user_id = (select auth.uid()));
   grant select, insert, update, delete on table public.your_table to authenticated;

2. 02

   The grant opens the table, so keep RLS on

   “Granting privileges allows access to your table through the Data API, so you should ensure you enable RLS and write appropriate policies to protect your data.” Supabase, Database API 42501 errors

   A grant lets the role reach every row. Turn RLS on and write policies before you grant, so the grant and the policies land in the same migration.

3. 03

   select * reads a restricted column

   “This includes using select *, as it expands to include forbidden columns.” Supabase, Database API 42501 errors

   If some columns are limited to certain roles, select * asks for them too and fails. Name the columns the app needs.

4. 04

   The table is in auth, vault or a custom schema

   “API roles cannot access certain schemas, most notably auth and vault.” Supabase, Database API 42501 errors

   The API roles can’t read auth or vault, by design. Keep the data you need in a public table, such as profiles. A custom schema has to be exposed in the API settings and granted to the roles.

5. 05

   Inserts fail with permission denied for sequence

   A serial id uses a sequence, and inserting needs usage on it too. Grant usage on the sequence, or use an identity column.

   grant usage, select on sequence public.your_table_id_seq to authenticated;

Checked against the vendor’s docs on November 9, 2026: Supabase troubleshooting: Database API 42501 errors; Supabase docs: Securing your API.

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