How is responsive design tested across devices and browsers?

Responsive design testing begins in the browser using Chrome DevTools Device Mode, which simulates a range of screen sizes and pixel densities. This allows rapid identification of layout breaks, overflow issues, and tap target sizing problems during the development phase before physical device testing.

BrowserStack provides cloud-based access to real devices and browsers for cross-browser and cross-OS testing at scale, covering Safari on iOS, Chrome on Android, and the full range of Windows and macOS browser environments. Automated testing tools like Playwright can run visual regression tests across breakpoints to catch responsive issues introduced by code changes. Testing should also include keyboard navigation, screen reader compatibility using NVDA or VoiceOver, and real network throttling to validate performance on mobile connections.