Responsive Tester completely free with no registration. Process data securely in your browser.
100% free, no signup required. Works entirely in your browser.
Open Responsive TesterUse the visual controls to design.
See the live preview update.
Copy the generated CSS code.
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.
