Sidephone - See mobile and desktop side by side

Your page at phone size in the side panel, next to the desktop version. Follows your tab as you work. Built for local development.

See the mobile version of your page while you build the desktop one. Sidephone puts a phone in Chrome's side panel and keeps it on the same page as your tab. Change a style, save, and both layouts update. A change that breaks the mobile layout shows up the moment you make it, without opening DevTools or switching views. It works on localhost as soon as it is installed. Every other site stays off until you turn it on. WHAT YOU GET • A live phone-sized copy of your page that follows your tab as you navigate and reload • Real responsive behavior: media queries, matchMedia and JavaScript-measured layouts respond to the device's width • The same device list as Chrome DevTools, from small phones to tablets and foldables • A device frame with rounded corners, camera cutout, status bar and browser bars, so you see how much room your page really has • An on-screen keyboard that appears when you focus a text field, to show what it would cover • Scroll sync, so the mobile view follows the desktop one • Pin, to hold the mobile view on one page while you browse elsewhere • Rotate, and pop out into a window at the device's exact size • Real size mode, calibrated to your monitor • Light and dark themes HOW SITE ACCESS WORKS Sidephone has access to localhost and 127.0.0.1 only. To mirror another site, click the toolbar icon while you are on it and approve Chrome's prompt for that one site. You can switch a site off again in the view options. PRIVACY Sidephone collects nothing. No analytics, no accounts, no network requests of its own. Your settings stay in your browser. GOOD TO KNOW • The side panel holds a second copy of the page. You stay logged in, but text typed into a form in your tab does not appear in the mirror. • It shows your layout at a device's width. It does not emulate touch input or the mobile user agent; use DevTools' device mode or a real phone for those. • A few sites cannot be shown inside another page. For those, Sidephone can open the page in a phone-sized window instead. Open source under the MIT license.