← Back to Backend Security Resources

    Supabase RLS Guide

    Complete guide to implementing Row Level Security in Supabase. Learn how to secure AI-generated database schemas with proper RLS policies for authentication and authorization.

    RLS is Not Enabled by Default

    AI-generated Supabase schemas rarely include RLS policies. Without explicit ALTER TABLE ENABLE ROW LEVEL SECURITY statements, all data is publicly accessible to anyone with your API key, even if you have authentication implemented.

    Supabase RLS Implementation Checklist

    Follow these 12 steps to properly implement Row Level Security in Supabase. Critical items must be completed for every table containing user data.

    Step 1

    Enable RLS on all tables

    Critical

    Activate Row Level Security on every table containing user data. Without RLS, all data is publicly accessible regardless of authentication.

    Step 2

    Create policies for SELECT operations

    Critical

    Define who can read data. Use user_id matching for user-owned records, role checks for admin access, and public flags for shared content.

    Step 3

    Create policies for INSERT operations

    Critical

    Control who can create new records. Typically allow authenticated users to insert their own data, with user_id automatically set to auth.uid().

    Step 4

    Create policies for UPDATE operations

    Critical

    Restrict updates to record owners or admins. Prevent users from modifying other users' data or changing ownership fields.

    Step 5

    Create policies for DELETE operations

    Critical

    Define deletion permissions. Usually limited to record owners or admins. Consider soft deletes for audit trails.

    Step 6

    Test policies with different user roles

    Critical

    Verify policies work correctly by testing as authenticated user, different user, admin, and anonymous user for every table.

    Step 7

    Protect sensitive columns

    Use SECURITY DEFINER functions for operations requiring elevated privileges. Hide columns like email, phone, or payment info from unauthorized users.

    Step 8

    Implement role-based access control

    Add role checks to policies using auth.jwt() → 'role' for admin, moderator, or custom role permissions.

    Step 9

    Add rate limiting to RPC functions

    Prevent abuse of custom functions by implementing rate limiting or requiring authentication for all RPC calls.

    Step 10

    Audit cross-table access patterns

    Review policies that join multiple tables. Ensure RLS on related tables prevents unauthorized data access through joins.

    Step 11

    Monitor policy performance

    Complex RLS policies can slow queries. Use EXPLAIN to analyze query plans and optimize policies with indexes.

    Step 12

    Document policy decisions

    Comment your RLS policies explaining business logic. Future developers need to understand why policies exist to maintain security.

    Common RLS Issues in AI-Generated Code

    RLS Disabled on Tables

    Critical

    AI-generated schemas often omit ALTER TABLE ... ENABLE ROW LEVEL SECURITY, leaving all data publicly accessible

    Missing DELETE Policies

    Critical

    Policies for SELECT/INSERT/UPDATE exist but DELETE is forgotten, allowing unauthorized data deletion

    Overly Permissive Policies

    High

    Using true as policy condition or auth.uid() IS NOT NULL without ownership checks grants access to all authenticated users

    Service Role Key in Frontend

    Critical

    Using service_role key in client code bypasses RLS entirely, exposing all database data

    Related Resources

    Supabase Security Guide

    Complete Supabase security best practices

    Database Security Best Practices

    Universal database security principles

    Authentication Implementation

    Implementing secure authentication

    Authorization Patterns

    RBAC and access control models

    Test Your Supabase RLS Policies

    VibeEval automatically tests your Supabase RLS policies across different user roles and scenarios to identify missing policies and overly permissive rules.

    Start Free RLS Audit