Vibe Coding Rebuild: Keep the Behavior, Lose the Slop
You described what you wanted, Lovable or Replit or Bolt built it, and for a while it worked. Then real customers showed up. Now something breaks every week, the AI burns credits debugging the same error in circles, and every new feature knocks over two old ones. The tool that got you a prototype in a weekend can’t get you a business.
This is normal, and it is measured. A May 2026 security scan found more than 2,000 vibe-coded apps publicly exposing sensitive data, most without basic authentication. Veracode’s 2025 report found AI-generated code carries 2.74 times more security flaws than human-written code. The prototype was never the problem; shipping the prototype as the product was.
The standard advice at this point is “hire a developer to clean it up.” That advice is outdated. Cleanup means paying someone to patch generated code that nobody, including the machine that wrote it, ever understood. The patches compound the mess. The better move starts from an observation about what your broken app actually is.
Your broken app is a working specification
The app in front of you does something valuable: it demonstrates, click by click, how your business is supposed to work. Which fields matter on the intake form. What happens when an order is paid but not fulfilled. Who gets the email and when. You spent weeks encoding that knowledge through prompts, and it lives in the running app right now, even if the code underneath is a hairball.
That behavior is the asset. The code is disposable. A rebuild that starts from this premise keeps everything you paid for and throws away only the part that was never worth keeping.
Why rebuilding beats cleanup now
Code used to be expensive, so the industry default was to salvage: refactor, patch, limp along. That calculus assumed the costly thing was writing code. It isn’t anymore. The costly thing now is recovering a precise understanding of what the app is supposed to do, and your running app already contains that understanding.
So the job is to extract it, write it down in a form a machine can verify, and then let the machine do what machines now do cheaply: write the code again, properly, with the written specification as the contract.
The process
Extract the stories. We point a coding agent at your existing codebase and running app and pull out the user stories: every workflow, every rule, every edge case your prompting baked in. This step is better established than it sounds: on research benchmarks, current models recover user stories from code with roughly 80% accuracy. You review the list. You will find things you forgot were in there, and things that were wrong all along. Both are worth knowing before a rebuild, not after.
Pin the behavior in executable specs. We write behavior specs against your running app using browser automation: log in as this user, submit this form, expect this result. These specs are written against your app’s behavior, not its code, which means they are portable. They describe your business, not your codebase.
Recover the business rules. Stories plus specs plus a read of the code surface the real rules of your operation, written in plain language you can check. This document outlives any codebase.
Rebuild against the specs. The new app is built spec first on Elixir and Phoenix, a deliberately boring stack chosen because it stays up and because it is measurably the language AI writes best. The specs written against your old app now run against the new one. When they pass, the rebuild is done, and “done” is a test result, not a vibe.
You keep everything. The stories, the specs, the rules document, and the code are yours. If you ever leave, you leave with the full written record of how your software works. No vendor, including this one, gets to hold that hostage again.
If the methodology sounds familiar, it should: this is characterization testing, the classic discipline for taming legacy code, described by Michael Feathers twenty years ago. It was always the right way to take over a codebase nobody understands. It was also expensive enough that almost nobody did it. Agents changed the price. What changed in 2026 is not the idea; it is that the idea finally costs less than the mess.
“Never rewrite from scratch.” Doesn’t that apply here?
The famous warning against rewrites exists because rewrites lose accumulated knowledge: all the edge cases and bug fixes encoded in the old code that nobody remembers. That warning is correct, and this process is built around it. Steps one through three exist precisely to capture that accumulated knowledge in written, executable form before a single line is rebuilt. A rewrite without specs is a gamble. A rewrite against specs extracted from the running system is a migration with a checklist.
The two situations also differ in what gets thrown away. The warning assumes battle-tested code carrying years of fixes. A vibe-coded app is months old and carries the opposite: generated bulk that was never reviewed. The knowledge worth keeping lives in the behavior, and the behavior is what we keep.
What it costs
This is Built with you: a conversation, then a quote, with a $500 minimum. Small apps with a handful of workflows sit near the floor. Real operations cost real money, and you will hear a specific number before anything starts, not an hourly meter. Once the rebuilt app is live, running it (email on your domain, live chat, publishing, reporting) is $100 a month per user, and the build tooling stays free.
Fair questions
Why should I trust this over an agency? Look at how cleanup agencies describe their work: audit, refactor, contact us for a quote. The deliverable is cleaner code, which you cannot evaluate, on a timeline you cannot verify. This process produces its proof as it goes. The stories and specs land in your hands early, in plain language, and you can check them against your own business before the rebuild starts. No cleanup service I have found delivers the specification as an artifact you keep; here it is the point. The method is the same one I use to build and run CodeMySpec itself, every day, in the open.
What do you need from me? Access to the running app and the code export, plus a few conversations. You are the oracle for step one: only you know which behaviors are features and which are bugs you have been living with.
Can I keep my current app running during the rebuild? Yes. Nothing in this process modifies your existing app or its code. The specs drive it through the browser the way a user would, against a test account or a staging copy, and you switch over when the new app passes.
What if I only want the specs? That is a valid stopping point. The stories and behavior specs are useful even if you take them to someone else, because they are written against your business, not against my stack.
Bring what is broken. Book a call with John and get a straight answer on whether a rebuild makes sense, and what it would cost.