What Actually Breaks When AI Builds Your App

I've personally triaged over 200 bug reports from vibe coders at this point. And after a while, you start seeing the same bugs show up again and again. It's almost predictable.

Doesn't matter which AI coding tool built the app. The failure modes are shockingly similar. Here's the breakdown.

The "Works in Preview, Dies in Production" Bugs

Auth Redirect Loops

This is the most common bug we see on VibeFix. The generated auth flow creates an infinite redirect after login. You log in, get sent to the callback, which sends you back to login, which sends you to the callback... you get it.

The fix is usually a misconfigured callback URL in your auth provider dashboard. Your preview URL and your production URL are different, but the auth config only has one of them. Check that first.

Database Access Policies

Row Level Security policies (or whatever access control your database uses) either block queries that should work, or they're missing entirely and everything is wide open.

I watched a founder spend three days confused because his app could read data in development but not in production. It was an access policy the AI forgot to generate. Check your database dashboard and look at what rules exist for each table.

Environment Variables

The number one cause of "it works on my machine." I can't say this enough.

Check that all your env vars are actually set on your deployment platform. Check that client-side variables have the right prefix (NEXT_PUBLIC_ for Next.js, VITE_ for Vite). And please, check that you're not accidentally exposing secrets to the browser. I've seen API keys in client bundles more times than I'm comfortable admitting.

The "AI Generated Bad Code" Bugs

Dependency Conflicts

AI tools will confidently suggest installing a package that directly conflicts with something already in your package.json. I've seen apps end up with two versions of the same library. Always check your package file before accepting any install suggestion.

Database Schema Mismatches

The AI generates a schema, then writes queries that don't match it. Column names are wrong, relationships are missing, types don't align. Compare your schema definition against the actual database calls. They're often just slightly out of sync.

Context Window Drift

Long AI sessions are a trap. After enough back and forth, the AI starts contradicting its own earlier suggestions. It forgets what it changed three messages ago. When you notice the outputs getting weird, just start a fresh chat. Don't try to correct it in the same thread.

The "Silent Failure" Bugs

These are the worst because everything looks fine from the outside.

Payment Webhooks

Stripe or Razorpay webhooks failing silently is a nightmare to debug because there's no error on the frontend. The payment goes through on the provider's side but your app never knows about it.

Check the webhook endpoint URL, verify the signature validation logic, and make sure your redirect URLs are correct. About 40% of our payment bounties come from this exact issue.

API Routes in Production

Classic. Your API works locally but dies in production. Almost always comes down to missing environment variables on the deployment platform or CORS settings that weren't configured for the production domain.

Mobile Responsiveness

The desktop version looks pixel perfect. Then you open it on your phone and everything overflows. Test at 390px width (that's an iPhone 14). Most of the time it's a container that doesn't have overflow-hidden or a flex layout that assumes desktop widths.

How to Get Unstuck

Auth is our most common bounty category. Session handling, token refresh, redirect flows. These are the areas where AI tools struggle the most, probably because auth logic has so many edge cases.

If you're posting a bounty on VibeFix, include which tool you used, be specific about what works and what doesn't, and attach screenshots of any errors. Copy your browser console output if you can.

Good bug reports get fixed in hours. Vague ones sit for days. That's just how it goes.

Post a bounty and get back to building.