Test responsive designs. Visual tool with live preview and CSS code output.
Note: Many sites block iframe embedding. Use the reference table below for dimensions.
@media (max-width: 430px) { /* iPhone 14 Pro Max styles */ }Use the visual controls to design.
See the live preview update.
Copy the generated CSS code.
Use the Responsive Tester when verifying that your website works correctly across different device sizes, debugging mobile layout issues, or validating responsive breakpoints. It is essential for frontend developers doing cross-device testing without physical devices. QA teams use it to verify responsive behavior before release.
Yes, test your designs at any custom viewport size or use preset device dimensions for popular phones, tablets, laptops, and desktop monitors. Adjust orientation (portrait/landscape), device pixel ratio, and user agent string to simulate specific devices accurately.
The Responsive Tester does not generate CSS — it displays your website or HTML at different viewport sizes to help you identify responsive design issues. Use the viewport information to write appropriate media queries in your CSS for each breakpoint.
Yes, save custom viewport configurations for devices specific to your project's target audience. The tool includes an extensive library of preset device sizes including iPhone, iPad, Samsung Galaxy, Pixel, and common laptop/desktop resolutions that are regularly updated.