← All errors · SupabaseSupabase auth errors

supabaseUrl is required

Exact error

Error: supabaseUrl is required.

What it means

createClient() was called with an undefined URL, usually because an environment variable is missing.

Likely causes

• Env var not set, misspelled, or not prefixed NEXT_PUBLIC_ / VITE_ for browser code.
• Env var missing in Vercel project settings.
• Dev server not restarted after editing .env.

How to fix it

1. Set the variables (Next.js):

   # .env.local
   NEXT_PUBLIC_SUPABASE_URL=https://<project-ref>.supabase.co
   NEXT_PUBLIC_SUPABASE_ANON_KEY=<anon-key>

2. For Vite apps (e.g. Lovable exports), use the VITE_ prefix and import.meta.env:

   const supabase = createClient(
     import.meta.env.VITE_SUPABASE_URL,
     import.meta.env.VITE_SUPABASE_ANON_KEY
   );

3. Restart the dev server, and add the same vars on Vercel then redeploy.

Prevent this next time

• Configure custom SMTP before launch so auth emails are not limited by the built-in test sender.
• Test signup, login, password reset and email confirmation on a staging project after every auth change.

Related errors

• Environment variable is undefined in the browser
• Invalid JWT / JWT expired