Dual Preview: Mobile View & Responsive Tester

See mobile and desktop views side-by-side. The ultimate responsive web tester and mobile simulator for faster frontend workflows.

Stop guessing how your website looks on a phone. Dual Preview is a free Chrome extension that shows you mobile and desktop views side-by-side — instantly, in one window, on any website. Up to 80% of web traffic is mobile, yet most of us still review and approve websites on a desktop screen. That means broken layouts, wrong font sizes, and cut-off buttons go live without anyone noticing. Dual Preview fixes that — paste any URL and see exactly what mobile users see, right next to the desktop version. No technical setup. No DevTools. No resizing windows. Just open it and see. 🚀 EVERYTHING YOU NEED: • Side-by-Side in One Click: Paste any URL and instantly see mobile and desktop simultaneously. Works on your own site or any website. • Real Device Viewports: Preview how your site looks on iPhones, Pixels, and Samsung devices your users actually own. • Mobile Simulator with Phone Frame: See the page inside a real-looking iPhone frame — just like your users do. • Multiple Panels: Compare three screen sizes at once or run two breakpoints in parallel. • Screenshot Both Views: Capture mobile and desktop in one image. Share in Slack, drop into Figma, paste into a ticket. • QR Code to Your Real Phone: Scan any URL straight to your phone and feel the actual experience in your hand. • PageSpeed Check: One click from any panel to PageSpeed Insights — no copying URLs. 🎯 WHO IT'S FOR: • Product Owners & Managers: Show stakeholders what mobile users actually see. No more approving desktop layouts and calling it done. • UX/UI Designers: Check your designs against real mobile screens as you work. Benchmark competitors with a single paste. • Content & Marketing Teams: Preview landing pages, articles, and campaign creatives on mobile before hitting publish. • Developers: Catch responsive bugs without toggling DevTools back and forth. Free. No account. Works on any website.