Supabase Not Connecting to Your Lovable App? Full Fix Guide

Supabase is the database behind the majority of apps built with Lovable, Bolt, and similar AI tools. It is powerful and free to start — but the connection between your AI-built frontend and Supabase backend has several failure points that are not obvious if you have not seen them before.

Step 1: Verify Your Environment Variables

The first thing to check is always the environment variables. In Lovable, go to Project Settings → Environment Variables and verify that VITE_SUPABASE_URL and VITE_SUPABASE_ANON_KEY are present and correct. Find the correct values in Supabase → Project Settings → API → Project URL and anon/public key.

Error: 401 Unauthorized

The anon key is wrong or missing. Note: there are two keys — the anon/public key (safe for frontend) and the service_role key (never use in frontend, it bypasses all security). Make sure you are using the anon key.

Error: relation does not exist

The table your app is querying does not exist in your database. The AI generated code referencing a table that was never created. Fix: Go to Supabase → Table Editor, check which tables exist, and create any missing tables with the correct columns.

Error: Empty Array (Data Should Exist)

You can see data in the Supabase Table Editor but your app returns empty arrays. This is almost always Row Level Security (RLS). Fix: Supabase → Table Editor → your table → RLS → Add Policy. For testing, add: FOR SELECT TO anon USING (true). For production, scope to authenticated users.

Cannot Insert or Update Data

Insert and update operations need their own RLS policies — a SELECT policy does not cover writes. Add separate INSERT, UPDATE, and DELETE policies for who should be allowed to make those changes.

Auth Redirect Errors After Login

After signing in, users land on an error page. Fix: Supabase → Authentication → URL Configuration → add your production URL and local development URL to both the Site URL and Redirect URLs fields. Supabase only redirects to URLs on this list.

Real-Time Not Working

Supabase real-time requires the table to have real-time enabled. Go to Supabase → Database → Replication → supabase_realtime publication → add your table.

Storage Uploads Failing

Storage has its own access control separate from database RLS. Go to Supabase → Storage → your bucket → Policies and add upload policies. Check that the bucket visibility (public or private) matches your use case.

If your app is still not connecting after checking all of these, the issue may be in the generated query code itself. Sharing your code with a developer for a quick review is usually the fastest path to a fix.