Missing Loading States in Vibecoded Apps

Throttle your network to 3G speed using browser DevTools and use the app normally. Every page transition, data fetch, and form submission should show some loading indicator — a spinner, skeleton, progress bar, or at minimum a disabled button state. If you see a blank area that eventually fills with content, that is a missing loading state.

Also check for layout shift. When content loads without a placeholder, surrounding elements jump around as the new content pushes them. This is particularly disorienting on mobile and is a direct result of not reserving space during the loading phase.

Use DevTools network throttling set to Slow 3G. This exaggerates loading times and makes missing states obvious. Navigate through the entire app at this speed, clicking every link and submitting every form. Take note of every moment where the UI gives no feedback.

Also test button states during async operations. Click a submit button and watch whether it shows a loading state or remains clickable. Double-click it rapidly. If the action fires twice with no indication that the first request is in progress, loading state handling is missing.

Add loading states to every async operation. Use React Suspense boundaries for code-split routes and data fetching. Disable buttons during form submission and show a spinner or loading text to prevent double submissions.

Implement skeleton screens for content areas that load data. Skeletons reserve the correct amount of space, preventing layout shift, and signal to users that content is coming. For lists and tables, show skeleton rows that match the expected content shape. This is far better than a blank area or a centered spinner.