Supabase security scanner
Supabase is secure when it is configured, and open when it is not. The gap between the two is Row Level Security and where you keep your keys. This page checks both on your live app, whatever built it.
Scan your Supabase app
What it means
Anyone can read this table without logging in. That can be deliberate, such as reference data or a public directory, or a missing access policy; only you can say which. xlogs read one row's column names and kept none of its values.
Why AI tools cause it
Supabase only limits who can read a table once you turn on Row Level Security (RLS) and write access rules for it. An AI tool can build a working app without doing that, and a table without RLS, or with a policy that lets everyone read, answers anonymous requests.
How xlogs checks it
xlogs finds your public Supabase URL and anon key in your app (the same ones your frontend uses), asks the database for its table list, reads one row from each listed table as an anonymous user, and flags any that return rows. Hosted Supabase refuses that list to public keys, so on a hosted project the result says the tables could not be checked. Read-only: it never writes or deletes.
The two Supabase mistakes worth checking first
First, tables with Row Level Security off. The public anon key your frontend ships is meant to be public, but without table policies it lets anyone read your data. Second, a service_role key that leaked into the frontend. That key bypasses RLS entirely, so it is the most dangerous thing you can expose.
The scan checks both. It tests your tables with an anonymous read, and it scans your shipped JavaScript for a leaked service key. It never flags the public anon key, because that one is supposed to be there.
How to fix it
The goal: Row Level Security is enabled on every table, and each table returns rows only to the users it is meant for: a private table answers no anonymous request, and a table that is public on purpose has a read policy that says so.
- Decide whether the affected spot is meant to be readable without a login
- If it is not, enable Row Level Security (RLS) on the affected spot and add a policy so only the users allowed to see a row can read it
- If it is, keep it public on purpose, and record that decision so a review does not reopen it
- Do not switch on a restrictive policy for a table your public pages read without a replacement read policy, or those pages stop working
- Re-check that an anonymous request returns what you decided it should
In my app (the spot the scan shows): anyone can read this table; confirm that is deliberate. Please make this true: Row Level Security is enabled on every table, and each table returns rows only to the users it is meant for: a private table answers no anonymous request, and a table that is public on purpose has a read policy that says so. Steps: Decide whether the spot the scan shows is meant to be readable without a login; If it is not, enable Row Level Security (RLS) on the spot the scan shows and add a policy so only the users allowed to see a row can read it; If it is, keep it public on purpose, and record that decision so a review does not reopen it; Do not switch on a restrictive policy for a table your public pages read without a replacement read policy, or those pages stop working; Re-check that an anonymous request returns what you decided it should. Then tell me exactly what you changed, and do not print any secret values back to me or write one into a commit message, a pull request description or a log.
Then verify: After you decide and deploy, xlogs repeats the same anonymous read of each table the database lists and reports what comes back: a table you made private should no longer return rows, and one you keep public still will. If the table list is refused, it says the tables could not be checked.
Full step-by-step fix guide, with a copy-paste block for each AI tool →
Common questions
Is Supabase secure out of the box?
No. Supabase gives you the tools to be secure, but a new table starts without policies. You have to turn on Row Level Security and write policies. A table created with SQL starts with RLS off, so until you turn it on, anyone with the public key can read it; with RLS on and no policy, every read is blocked, and policies then open what should be open.
Which Supabase key is safe to ship in the browser?
The anon key is public and safe to ship in the browser; it obeys your RLS policies. The service_role key ignores RLS and can do anything, so it must stay server-side only. If a service key is in your frontend, treat it as an emergency and rotate it.