Vibe coding, building an app by describing what you want to an AI tool rather than writing the code yourself, is a little like assembling furniture with the instructions thrown away. It works. The thing stands up, it holds weight, you can sit on it. Right up until the point it very much does not, and you have no idea which screw was the one holding everything together.
This is not an argument against using AI tools to build. It is a plain-language list of what tends to be underneath once someone actually looks, so you know what to check before you find out the hard way.
Security Gaps
This is the category that causes the most real damage, and it is almost invisible from the outside. API keys, database passwords, and other secret credentials often get written directly into the code rather than kept separately, sometimes ending up in a public repository where automated scanners find them within hours. Database queries are frequently built by joining pieces of text together instead of using safe, separated parameters, which opens the door to an attacker manipulating your database directly. Login and permission checks are often incomplete or missing entirely on parts of the app that were added later. There is frequently no limit on how many times someone can attempt an action like logging in, which leaves the door open to automated attacks. And in tools like Firebase or Supabase, the settings that should stop one user from reading another user's data are sometimes left switched off entirely, which is exactly as serious as it sounds.
Structure and Maintainability Gaps
Beyond security, there is the question of whether the code can actually be worked on going forward. Apps built across several different AI sessions, or with more than one AI tool, often end up with the same job done three different ways in three different places, because each session had no memory of how the last one solved it. There are usually no automated tests at all, which means every future change is essentially a gamble rather than something that can be checked automatically. Specialists doing this kind of cleanup typically aim for a minimum of around 70 percent test coverage on the parts of an app that touch money or user data specifically, precisely because that is where an untested mistake costs the most. Error handling is often missing too, so one unexpected input can crash an entire feature instead of failing gracefully.
Problems You Only Discover Once Real Users Show Up
The most frustrating category is the one that does not show up in testing at all. An app can work perfectly when you are the only person using it and fail the moment real traffic, real concurrent users, or a real edge case arrives, because the AI optimised for the demo, not for production. Worse, some failures are silent: the app does not crash, it just quietly does the wrong thing, which means nobody notices until real damage has already been done. And there is a specific trap worth knowing about: fixing one AI-generated bug by re-prompting for a patch frequently introduces a new one, because regenerating code around a symptom tends to paper over the actual structural problem rather than fixing it.
How Many of These Apply to You
Almost no app has every single item on this list. That is not really the point. The point is that most vibe-coded apps have at least a few of them, quietly, and the ones in the security section are the ones that turn from "we should get to this eventually" into an actual incident without much warning. If you read through the security section above and recognised your own app in more than one line, that is worth acting on before it becomes something more expensive than a cleanup. Our piece on whether vibe coding is actually safe goes deeper into the real research behind how common these problems are, and if you want to know what actually happens when someone looks at your specific code, what a vibe code cleanup specialist actually does explains the process. For the fuller picture of how bad code drives up cost even without a security incident, our earlier piece on why messy code costs your business more than you think is worth reading too.
If several of these already sound familiar, our code cleanup service starts with reading through exactly this list against your actual codebase, not a generic checklist.