How to fix 42501: Permission denied for table/schema (RLS error) in Supabase

SupabaseINTERMEDIATEHIGH

PostgreSQL error 42501 indicates insufficient privileges to access a table, commonly caused by missing RLS policies, incorrect grants, or authentication issues in Supabase. This error occurs when your application tries to read, insert, or update data without proper permissions configured.

What this error means

The error 42501 is a PostgreSQL permission denied error that Supabase inherits. It occurs when your database role (anon, authenticated, or service_role) lacks the necessary privileges to perform an operation on a table. This is typically caused by Row Level Security (RLS) policies being too restrictive, missing altogether, or by insufficient database grants. RLS is a PostgreSQL feature that controls row-level access based on the current user. When RLS is enabled on a table without proper policies defined, all access is denied by default. The error can also occur when accessing tables in custom schemas without proper grants, or when database object ownership and permissions are not correctly configured.

How to fix "42501: Permission denied for table/schema (RLS error)"

1Check if RLS is enabled and policies exist

First, verify whether RLS is enabled on your table and what policies exist:

sql

-- Check if RLS is enabled
SELECT relname, relrowsecurity
FROM pg_class
WHERE relname = 'your_table_name';

-- View all policies on the table
SELECT policyname, cmd, qual, with_check
FROM pg_policies
WHERE tablename = 'your_table_name';

If the table has relrowsecurity = true but no policies appear, RLS is blocking all access. If no policies exist at all, create them (see next steps).

2Create a SELECT policy for read access

If RLS is enabled but you lack SELECT policies, create one. For public read access:

sql

CREATE POLICY "Enable read access for all users" ON your_table_name
  FOR SELECT
  USING (true);

For authenticated users only:

sql

CREATE POLICY "Enable read for authenticated users" ON your_table_name
  FOR SELECT
  USING (auth.role() = 'authenticated');

For row-level filtering (e.g., users see only their own rows):

sql

CREATE POLICY "Users can see their own rows" ON your_table_name
  FOR SELECT
  USING (auth.uid() = user_id);

Replace your_table_name, user_id, and the conditions with your actual table and column names.

3Create INSERT and UPDATE policies if needed

If you're getting 42501 on INSERT or UPDATE operations, create policies for those:

sql

-- Allow authenticated users to insert rows
CREATE POLICY "Enable insert for authenticated users" ON your_table_name
  FOR INSERT
  WITH CHECK (auth.role() = 'authenticated');

-- Allow users to update only their own rows
CREATE POLICY "Users can update own rows" ON your_table_name
  FOR UPDATE
  USING (auth.uid() = user_id)
  WITH CHECK (auth.uid() = user_id);

The USING clause filters which existing rows can be modified. The WITH CHECK clause validates new/updated row data.

4Fix grant issues (if RLS is not the problem)

Sometimes the issue is grants, not RLS. Check if the anon/authenticated roles have SELECT privilege:

sql

-- Check grants on your table
SELECT grantee, privilege_type
FROM information_schema.role_table_grants
WHERE table_name = 'your_table_name';

If grants are missing, add them:

sql

-- Grant permissions for the anon role
GRANT SELECT ON your_table_name TO anon;
GRANT INSERT ON your_table_name TO anon;

-- Grant permissions for the authenticated role
GRANT SELECT, INSERT, UPDATE ON your_table_name TO authenticated;

-- For custom schemas, also grant schema usage
GRANT USAGE ON SCHEMA my_schema TO anon, authenticated;
GRANT SELECT ON ALL TABLES IN SCHEMA my_schema TO anon, authenticated;

5Verify your authentication token and user context

Ensure your application is sending a valid JWT token and that Supabase can identify the user:

javascript

// In your frontend, ensure you're signed in
const { data: { user } } = await supabase.auth.getUser();
console.log("Current user:", user?.id);

// Use authenticated client for queries (not anon key)
const { data, error } = await supabase
  .from('your_table_name')
  .select()
  .eq('user_id', user.id);

if (error) console.error("Error:", error.code, error.message);

For backend operations, ensure you're using the service_role key which bypasses RLS:

javascript

const supabase = createClient(url, SERVICE_ROLE_KEY); // Bypasses RLS

6Test policies with correct role context

Use Supabase's authenticated/anon testing or directly test with the correct roles:

sql

-- Test with anon role
SET ROLE anon;
SELECT * FROM your_table_name LIMIT 1;

-- Test with authenticated role
SET ROLE authenticated;
SELECT * FROM your_table_name LIMIT 1;

-- Reset to postgres
RESET ROLE;

If a policy fails in one role but works in another, the policy logic is role-specific. Review the policy condition (USING/WITH CHECK) to ensure it's correct for that role.

7Disable RLS as a temporary diagnostic step

If you're unsure whether the issue is RLS or grants, temporarily disable RLS to diagnose:

sql

ALTER TABLE your_table_name DISABLE ROW LEVEL SECURITY;

If the error disappears, the problem is RLS policies. If it persists, the problem is grants. Once you identify the issue, re-enable RLS:

sql

ALTER TABLE your_table_name ENABLE ROW LEVEL SECURITY;

Note: Use this only for diagnosis. RLS should be enabled in production for security.

How to fix 42501: Permission denied for table/schema (RLS error) in Supabase

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How to fix "42501: Permission denied for table/schema (RLS error)"

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