The demo works, and that is usually where the trouble starts. Someone describes an idea to a model, watches a functioning app appear in an afternoon, clicks through the happy path twice, and starts thinking about a domain name. Vibe coding has collapsed the distance between an idea and something you can actually click on, which is genuinely useful, but it has not collapsed the distance between something that runs and something that survives contact with real users.
The gap matters because the code you did not write is still code you now own. A generated app carries assumptions you never made explicit: which fields it trusts, which routes it guards, which library versions it pulled in while you were busy describing features. None of that is visible from the outside, and none of it surfaces when you test the way you built, by clicking around and checking whether the screen looks right.
So the work before deployment is not a formality. It is a short, structured set of passes, each asking a different question of the same application, and each catching a class of failure the others will miss. Five stages cover most of what goes wrong: functionality, security, dependencies, authentication, and input validation.
Functionality Testing Establishes the Baseline
Start by proving the app does what you asked for, not what you remember asking for. Write down the handful of flows that define the product, then walk each one deliberately: the signup, the core action, the edit, the delete, the empty state nobody thinks about until a first-time user hits it. Generated apps are often strong on the primary path and thin everywhere else, because the prompt described a success case and the model obliged.
Automate the flows that would ruin your week if they regressed. The Playwright team’s testing best practices argue for verifying user-visible behavior rather than implementation details, and that advice suits generated code unusually well, since the internals may change substantially the next time you ask for a feature while the user-facing contract stays put. Six to ten solid tests beat a hundred shallow ones.
Security Testing Deserves Its Own Pass
Functionality testing asks whether the app works. Security testing asks what happens when somebody tries to make it misbehave, a different question with different answers. Point a scanner at the running application, read what it finds, then read the code it flagged.
Findings arrive with severity scores, and those scores reward a little understanding. The CVSS v4.0 specification from FIRST splits severity into base, threat, and environmental groups, which is a formal way of saying that a flaw’s real weight depends on your deployment and not on the flaw alone. A high base score on an endpoint nobody can reach may matter less than a medium one sitting on your login page. Retool’s guide to how to safely deploy vibe-coded apps is a sensible companion while you triage.
Dependency Checks Catch the Risks You Did Not Write
Most of a generated app is not generated; it is imported. The model reaches for familiar packages, those packages reach for others, and within a few layers you are running code from maintainers you have never heard of, in versions chosen by a system with no view of this month’s advisories.
Software composition analysis handles that cheaply. Tools in the category, Snyk Open Source among them, walk the full dependency tree including the indirect packages developers rarely realize they are calling, and flag both known vulnerabilities and license terms that could become somebody’s problem later. Upgrade what has a fix, drop what you are not using, and pin the rest so the app you tested is the app you deploy.
Authentication and Authorization Need Explicit Proof
Ask a model for a login screen and you will get a login screen. Whether every route behind it actually checks the session is a separate matter, and it is the most common hole in an app that otherwise looks finished.
Test it directly rather than by inspection. Log in as one user, capture the URL of something that belongs to them, log out, and request it again. Then log in as a second user and request the first user’s resource. Do the same against your API routes, because a front end that hides a button proves nothing about the handler behind it. Check the dull settings too: session expiry, password reset, and where tokens are stored.
Input Validation Is the Last Line Between Users and Your Data
Every field a user can type into is an instruction to your application, and generated apps tend to validate in the browser, where validation is a courtesy rather than a control. Anything arriving at the server needs checking there too, against an allowlist of what you expect rather than a blocklist of what you fear.
Try the obvious hostile inputs on each form: a very long string, a negative number where a quantity belongs, a quote character in a text field, a script tag in anything rendered back to the page. Then send a request your interface never would, with a renamed field. Parameterized queries and strict schema validation on the request body handle most of this, and both are quick to add once you know which handlers lack them.
What to Do With What You Find
None of this takes long on a small app. An afternoon covers all five passes, and the findings tend to cluster: a couple of unguarded routes, a stale dependency, a form that trusts the browser. Fix them, rerun your tests, and you can ship without checking your phone all evening.
The habit matters more than the checklist. Every time you ask a model for a feature you accept a fresh batch of code you did not write, so the same five questions come back around, and a small automated suite answers most of them for you. If you want to go deeper on tooling for each stage, this roundup of software testing tools maps the categories reasonably well.
Shipping fast is not the problem. Shipping fast without ever asking what you shipped is, and the distance between the two is a few hours of deliberate suspicion.
FAQs About Testing Vibe-Coded Apps
1. What is vibe coding, and why does testing matter?
Vibe coding is an approach to software development where developers use AI prompts to generate application code. Testing is essential because generated code may contain bugs, security vulnerabilities, outdated dependencies, or missing access controls.
2. What should you test before deploying a vibe-coded app?
Before deployment, test functionality, security, dependencies, authentication and authorization, and input validation. These checks help identify common issues before they affect real users.
3. How do you test the functionality of an AI-generated application?
Test the main user journeys, including signup, login, creating and editing records, deleting data, and handling empty states. Tools such as Playwright can automate these tests and help catch regressions after code changes.
4. How can you identify security vulnerabilities in a vibe-coded app?
Use security scanners, review flagged code, check access controls, and test API endpoints for unauthorized access. Prioritize vulnerabilities based on their severity and the potential impact on your application.
5. Why is dependency scanning important for AI-generated code?
AI-generated applications often rely on third-party libraries and indirect dependencies. Dependency scanning helps identify known vulnerabilities, outdated packages, and potential license issues before deployment.
6. How can you check authentication and authorization in a vibe-coded app?
Test protected routes and API endpoints while logged out and while signed in as different users. Verify that users cannot access another user’s private data and that sessions, password resets, and tokens are handled securely.
7. Can you deploy a vibe-coded app without writing automated tests?
You can, but it increases the risk of bugs and security issues reaching production. Even a small automated test suite covering critical user flows can make deployments more reliable and reduce future maintenance work.
