5 common Supabase errors in Lovable apps (and what they mean)

Lovable uses Supabase for your database, logins and backend functions. When something goes wrong there, the error messages can be confusing. Here are five you might see and what each one is really telling you.

1. "new row violates row-level security policy"

Supabase has a security lock on each table. This means your app tried to save data and no rule allowed it, often because you weren't logged in or no policy exists yet. Don't turn security off. Add a policy instead. See the fix.

2. "AuthSessionMissingError: Auth session missing!"

Your app asked for the logged-in user before the login finished, or the redirect after login lost the session. See the fix.

3. "Edge Function returned a non-2xx status code"

A backend function crashed or refused the request. The real error is in the function's logs in Supabase, and it's often a missing secret like an API key. See the fix.

4. "Invalid API key"

The Supabase URL or key in your app is wrong, swapped, or from a different project. See the fix.

5. "TypeError: Failed to fetch"

The request never reached the server. That can be a wrong URL, a server that's down, or a browser security (CORS) block. See the fix.

Seeing something else? Paste it into Unstuck and pick Lovable.