What is the most common vibe coding mistake?

Accepting generated code without reading it. Because AI-generated code compiles and renders, there is no moment that forces you to check whether it handles errors, empty states or network failures — so nobody does, and the gap surfaces in production.

Are vibe coding mistakes a security risk?

Three of them are: secrets pasted into client-side code (anything in your frontend bundle is public), permissions checked only in the UI (hiding a button does not protect the endpoint behind it), and backend tables left world-readable because row-level security was never switched on. All three leave the app behaving perfectly while it is exposed.

How do I test a vibe-coded app if I am not technical?

Do a five-minute manual pass with the browser console open: sign up as a brand-new user, in a phone-sized window, on a throttled connection, and submit every form empty once. Then add automated persona testing so someone who does not know your happy path exercises the app for you.

Should I ask the AI to write tests for its own code?

Not as your only safety net. A test suite written by the same assistant that wrote the bug will often assert the buggy behaviour as correct. Start with one automated critical path, a logged-out check on every data-bearing endpoint, and a bug intake that captures context automatically.

9 Common Vibe Coding Mistakes That Ship Bugs to Users

Q: Why does AI-generated code fail differently from hand-written code?

Hand-written code tends to fail where the author found the problem hard. AI-generated code tends to fail where the author never thought to specify anything, because the model filled the gap with something plausible rather than something correct — so the bugs only appear under real conditions like slow networks, duplicate accounts or expired sessions.

The most common vibe coding mistakes are shipping code nobody read, testing only the happy path, enforcing permissions in the UI instead of on the server, and regenerating a broken file instead of debugging it. None of these are failures of the model. They are failures of the loop around it: tools like Cursor, Bolt, Lovable, v0 and Replit produce code that compiles, renders and looks finished, so there is never a moment that forces a human to check whether it actually works. The fix is a verification step, not a better prompt.

What are the most common vibe coding mistakes?

Across vibe-coded apps, the same handful of failures show up again and again. They cluster into three groups: things you never read, things you never tested, and things you never secured.

Mistake	What it looks like in production	The cheap fix
Accepting code you did not read	A function silently swallows errors; nobody knows until a user reports "nothing happens when I click save"	Skim every generated diff for error handling and network calls before accepting
Happy-path-only testing	Works when you type a valid email; breaks on an empty form, a slow network, or a duplicate signup	Try the three ugly inputs: empty, wrong, and twice
Auth enforced in the UI	A hidden button still has a live endpoint behind it	Check the server route, not the component
Database left open by default	Client-side keys can read tables they should never see	Turn on row-level security and test with a logged-out client
Regenerating instead of debugging	Each "fix it" prompt rewrites working code and introduces a new bug	Reproduce first, read the console, change one thing
No loading or error states	The app looks frozen on slow connections	Throttle the network in devtools and watch what the user sees
Never opening the browser console	Warnings and failed requests pile up invisibly	Keep the console open while you click through

If you only fix one thing on this list, make it the last one. The browser console is free, already installed, and quietly reports most of the failures above before a user ever hits them.

Why does AI-generated code fail differently from hand-written code?

When a developer writes a feature by hand, the hard parts feel hard. You notice you have not handled the empty state because you had to decide what to render. Generated code removes that friction: the empty state is either handled well or absent entirely, and both outcomes look identical in the editor.

That changes the shape of the bugs. Hand-written code tends to fail at the parts the author found confusing. AI-generated code tends to fail at the parts the author never thought to specify — because the model filled them in with something plausible rather than something correct. The result is code that is syntactically clean, stylistically consistent, and wrong in ways that only surface under real conditions: a real user with a slow phone, a duplicate account, an expired session, or a 3,000-character paste into a field you assumed would hold a name.

A second effect compounds it. Because generating code is fast, vibe-coded apps accumulate features faster than any human reads them. The codebase grows past the point where the person who "wrote" it can hold it in their head, and that happens in days rather than months. We covered the full picture in is vibe-coded code safe to ship.

Which vibe coding mistakes are actual security risks?

Three of them, and they are worth separating from the cosmetic bugs because the blast radius is different.

Secrets in client-side code. Anything in your frontend bundle is public. An API key for a paid service pasted into a component is readable by anyone who opens devtools, whether or not it is in a variable named secret. Keys belong in server-side environment variables, behind an endpoint you control.
Permissions checked only in the UI. Hiding an admin button does not protect the route behind it. If the endpoint does not independently verify who is calling it, the feature is open to anyone who can guess the URL.
Backend tables left world-readable. Managed backends hand you a public anon key on purpose — it is designed to be shipped in the browser, and the actual access control is a separate setting. If row-level security is off, that key reads the table. Verify it the direct way: sign out, then try to fetch a record that belongs to another user.

These three share a property that makes them dangerous: the app behaves perfectly while they are broken. Nothing is slow, nothing errors, no user complains. You find out from a bill, a leak, or a stranger.

How do you catch these mistakes without a QA team?

You need something that exercises the app the way a stranger would, because you cannot do it yourself. You know which button to click and in what order, and that knowledge is exactly what hides the bugs. Three practical layers, cheapest first:

A five-minute manual pass with the console open. Sign up as a brand-new user, on a phone-sized window, on a throttled connection. Submit every form empty once. This catches more real bugs per minute than any other activity available to a solo builder.
Structured reports when someone else finds something. When a friend, client or early user hits a bug, "it's broken on my end" costs you an hour of guessing. Snap turns a right-click into a report carrying the screenshot, console errors, network requests and browser context — so you debug the failure instead of reconstructing it.
Automated exploration by personas who do not know your happy path. Sims runs AI personas through your app the way different real users would — the impatient one, the one who double-submits, the one who pastes nonsense into the name field — and reports what broke. AutoSim then locks the flows that matter into E2E tests that repair their own selectors when your AI assistant renames a component next week.

What does a minimum QA safety net look like for a vibe-coded app?

Not a test suite. A test suite written by the same assistant that wrote the bug will happily assert the buggy behaviour. Start with three things instead:

One critical path that must never break. Usually signup through to the first moment of value. Automate that one, and nothing else, until it is genuinely stable.
A logged-out check on every data-bearing endpoint. One pass, repeated after any change to auth or schema.
A bug intake that captures context automatically. The gap between "something's wrong" and a reproducible report is where most solo-builder time disappears.

That is the whole floor. It is deliberately small, because a QA process you skip is worth less than a five-minute one you actually run. For the step-by-step version, see how to QA a vibe-coded app, and for the wider context on automated verification, our complete guide to AI QA.

The pattern underneath all of them

Every common vibe coding mistake on this page is the same mistake wearing different clothes: generation got faster and verification did not. You can close that gap with discipline — reading every diff, testing every edge case by hand — or you can close it by making verification as automatic as generation already is. Most people who ship regularly end up choosing the second.

Try Klavity free and let AI personas find the edge cases in your vibe-coded app before your users do.