How to Test Error Handling in Vibecoded Apps

Use Chrome DevTools to simulate offline mode and verify every page shows a meaningful message instead of a white screen or spinner that never resolves. Test individual API failures by using DevTools to block specific network requests — the feature that depends on that API should show an error state while the rest of the app continues to work.

Test slow network conditions (Slow 3G) and verify that timeout handling works. AI-generated fetch calls often have no timeout, so a slow API response leaves the user staring at a loading spinner indefinitely. Also test what happens when the API returns an unexpected response format — the app should not crash on malformed JSON or missing fields.

If your app uses React, verify that error boundaries are in place so a crash in one component does not bring down the entire page. Use React DevTools to trigger errors in individual components and check that the boundary catches the error and shows a fallback UI. AI-generated apps frequently have a single error boundary at the root level or none at all.

Test recovery from errors: after an error boundary catches an error, the user should be able to retry or navigate away. Many vibecoded error boundaries show an error message but provide no way to recover, leaving the user stuck until they refresh the page. Include a retry button and a way to navigate to a working part of the app.

Trigger every error condition you can think of and verify that the user sees a helpful, human-readable message — not a stack trace, error code, or the word 'undefined'. AI-generated code frequently exposes technical error messages directly to users, including database errors, server stack traces, and raw error objects like [object Object].

Verify that error messages provide actionable guidance. 'Something went wrong' is not helpful. 'Could not save your changes. Please check your connection and try again' is much better. Also test that errors are logged properly on the backend for debugging — swallowing errors silently is as bad as showing them to users.