Trusted by teams worldwide
Firstversionist creates software used by companies like:
Polypane is built for developers like you.
Everything you need to develop truly responsive web apps and sites, together in a single browser.
Stop resizing your browser
Emulate real devices, use your CSS breakpoints or pick your own dimensions. No resizing needed.
Get the full overview, your way
Line your viewports up horizontally or vertically, focus in on a single viewport in focus mode or get the classic browser style in our full mode. Your choice.
Sync all your actions
Interacting with one device means interacting with all of them. It just works.
Build pixel perfect sites
Compare an image with the expected design to your live site with different comparison modes built right in.
* We don't think sites have to be pixel perfect. But getting close is nice.
Devtools like you're used to, with support for devtools extensions too.
More than just responsive design tools
Over 15 overlays let you easily check contrast and accessibility, edit your page visually, test for visual impairments and more.
Light and dark modes
Polypane comes in a light and dark theme, so it always fits in with your desktop.
Full page screenshots
You want best in class screenshots, and we have them. No other browser comes close in terms of rendering accuracy. We also support screenshots of all your viewports.
Everything you need to make awesome web experiences
Live reloading, touch and mobile emulation, dev tools extensions, workspaces and css breakpoint detection. Polypane has it all.
Start a 14 day trial of the browser that makes you awesome.Try for free
Praise for Polypane
Polypane is easily one of the most useful tools for modern web designers and developers.
Polypane are building a smart design environment where you can preview your designs across a multitude of browsers, devices and viewports.
Discovering Polypane was a game-changer to how I develop responsive websites. I couldn't imagine going back to using the Chrome inspector.
If you’re developing a website, Polypane comes in quite handy. Already an essential tool.
An invaluable tool for responsive website testing. A must-have for front-end developers.
Polypane quickly became an indispensable part of my workflow. With a tool like this, you have no excuse not to create great, responsive experiences!
A vital part of the web development toolkit for testing and troubleshooting responsive design.
Hi! I'm Kilian, the creator of Polypane.
I'm building my own browser.
Before I started doing that, I ran an internet agency. I constantly felt pressure from clients to develop sites faster and here I was, resizing my browser to work on each screen size one-by-one. I was wasting so much time just resizing my browser.
More than that, I saw many opportunities to make the process so much better, to make a browser that works for me instead of against me. So that is my goal: make the ultimate browser for developers and designers.
Polypane can easily cut your development time in half, and I'm just getting started.
A browser that makes you awesomeTry for free