RLS (Row Level Security)
Rules that decide who can see what data in your database.
What is RLS (Row Level Security)?
Without RLS, any user could potentially read everyone else's data. RLS lets you set rules like "users can only see their own records." It's one of the most important security settings in Supabase and one of the most commonly forgotten.
Think of it like a filing cabinet where each drawer only opens for the right person. Without RLS, every drawer is unlocked for everyone.
In Vibe Coding
RLS is the most commonly forgotten security setting in Lovable and Cursor apps. Without it, any user can read every other user's data. Supabase has RLS turned on by default, but you need to create policies for your tables.
Example
For example: You build a notes app. Without RLS, User A can see User B's private notes. With RLS, the database automatically blocks access — each user only sees their own notes.