Guide
My builder says the app is tested, but my customers hit problems
Updated
Builders now test your app for you inside the editor, and it all passes. Then the first real customers get stuck on sign-up, email, payment or a phone screen.
Why it happens
By their own docs, Lovable's browser testing, Replit Agent's app testing and Base44's testing agent test the preview or a separate test copy, not your live published app (Lovable, Replit, Base44). The live app differs in four ways.
Possible causes
- The address: sign-in, email links and payment redirects have to trust your live domain, but in the preview they trust the preview's address.
- The keys: live payment keys, email sending and database rules are often set up only for testing.
- Real email: a sign-up email has to actually arrive from your own domain and not land in spam.
- Real phones: small screens, slow networks and the in-app browsers of Facebook and Instagram, where shared links open.
- Every publish can break something that worked before: a new feature, a "fix", a setting that did not carry over.
You can't see it yourself
You're signed in, your customers aren't. The builder is checking its own work, in the preview, while you are signed in. A first customer is a stranger on the live app.
Related: It works in the preview but breaks after I deploy · Sign-up or login broken after publishing: users bounce back to login or land on localhost · The sign-up confirmation email never arrives · My vibe-coded app is broken and I don't know who can help
VibeFix is independent. Lovable, Bolt, Replit, Base44, v0, Supabase, Firebase, Stripe and Vercel are trademarks of their owners.
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