Over 60% of web traffic is mobile. Your application probably looks great on the developer's 27-inch monitor. It might be unusable on a phone.
Responsive bugs are uniquely dangerous because developers rarely test on mobile devices. They build on desktop, test on desktop, and push to production. The first person to experience the mobile layout is a real user.
Common responsive bugs AI coding tools introduce: buttons that overlap on small screens, forms where the keyboard covers the submit button, navigation menus that don't collapse properly, text that overflows containers, touch targets too small to tap accurately, and horizontal scrolling on pages that shouldn't scroll.
These bugs don't produce errors. They produce frustrated users who can't complete their task and leave.
TestSprite tests your application across viewport sizes as part of the standard test suite. Mobile layouts, touch interactions, and responsive breakpoints are verified on every PR. When a code change breaks the mobile experience, the visual snapshot shows exactly what went wrong.
For teams building with AI coding tools, mobile testing shouldn't be an afterthought. It should be automatic.