Preview how any website looks on different screen sizes and devices.
Responsive Tester is a free, browser-based tool designed for developers, writers, and quality-focused professionals. Test how any website looks on different screen sizes. Preview iPhone, iPad, laptop, and desktop views. Free online responsive design tester. Everything runs locally in your browser using JavaScript — no data is ever sent to a server, making it completely private and secure. The tool is designed to be intuitive and beginner-friendly while still offering advanced features for power users. It loads instantly with no installation required and works offline once loaded. Use it as often as you need — there are no daily limits, no watermarks, and no hidden fees.
Who is this for? Responsive Tester is ideal for professionals, students, freelancers, and hobbyists who want quick, reliable results without installing software or creating accounts. Whether you are on a laptop, tablet, or phone, it works seamlessly in any modern browser.
Yes! Responsive Tester is completely free with no signup required. It runs entirely in your browser — your data never leaves your device.
Paste or enter your data in the input area. The tool analyzes it instantly in your browser and shows detailed results. No data is sent to any server.
Absolutely. Responsive Tester runs 100% client-side in your browser using JavaScript. No data is uploaded, stored, or shared with any server. Your privacy is guaranteed.