Common errors · Lovable, Bolt, Cursor projects on Vercel, Netlify, Railway

Environment variables undefined in production (Vite, Next.js)

Cause Client variables are baked in at build time and need the VITE_ or NEXT_PUBLIC_ prefix; the host never received your .env.
Fix Add each variable in the host dashboard with the right prefix, then rebuild. Secrets stay server-side, without the prefix.

Have it fixed for you, 290 EURSee the fix step by step

Everything works in the editor preview, the deployed site shows a blank page and this error in the console. The variables existed in the builder, not on your host.

Where it breaks

Which case is yours?

1. Client-side variables are baked in at build time. Vite only exposes names starting with VITE_, Next.js only NEXT_PUBLIC_. Adding them after the build changes nothing until you rebuild.
2. The .env file is not committed (correctly), so the host never received the values.

The fix, step by step

1. List what the code reads.

   grep -rhoE "(import\.meta\.env|process\.env)\.[A-Z0-9_]+" src app | sort -u

2. Add each one in the host dashboard with the right prefix (VITE_SUPABASE_URL, VITE_SUPABASE_ANON_KEY...), for the production environment, then trigger a new build.
3. Only public values go behind VITE_ or NEXT_PUBLIC_. The Supabase service_role key, Stripe secret key and any API secret stay server-side (Edge Function, API route) without the prefix.
4. Fail loudly at start-up so a missing value never ships again.

   if (!import.meta.env.VITE_SUPABASE_URL) throw new Error("VITE_SUPABASE_URL missing at build time");

How to check it is fixed

View the page source of the deployed build and search for your Supabase project ref: it is present, and no sk_live_ or service_role string is.