How do I fix "supabaseUrl is required"?

Add the Supabase URL and anon (publishable) key to your host's environment settings. Use the right prefix for code that runs in the browser (NEXT_PUBLIC_SUPABASE_URL, VITE_SUPABASE_URL). Redeploy, then check the browser console again. Never give the service role key a public prefix.

supabaseUrl is required

Supabase
Vercel
Netlify

What it means

The Supabase client was created with an empty project URL: the environment variable it reads is not set where the app is running.

Why it happens

The variable is in your local .env but not in your hosting provider's settings.
Browser code reads a variable without the public prefix (NEXT_PUBLIC_ or VITE_), so it is undefined in the page.
The variable was added after the last deploy and needs a rebuild.

How to fix it

Add the Supabase URL and anon (publishable) key to your host's environment settings.
Use the right prefix for code that runs in the browser (NEXT_PUBLIC_SUPABASE_URL, VITE_SUPABASE_URL).
Redeploy, then check the browser console again.
Never give the service role key a public prefix.

Let your AI find the cause

Paste this into Claude Code, Cursor, Lovable or whichever AI built your app. It looks first and changes nothing until you have read the answer.

My app throws 'supabaseUrl is required'. Without changing anything yet, show me where the Supabase client is created, which environment variables it reads, whether each runs in the browser or the server, and which must be set in my host.