
The browser for ambitious web developers
Polypane is a Chromium-based development browser displaying sites in multiple synchronized viewports simultaneously, consolidating 25+ debug tools and 80+ accessibility tests for responsive, accessible web development.
Multiple screen sizes with synced scrolling, clicks, and forms
WCAG scanning, color contrast, focus order, screen reader simulation
Z-index, CSS grid/flexbox, dark mode, visual regression
Pre-configured presets with CSS media query detection
Color blindness, tunnel vision, dyslexia simulation
Zero-config reload for changed CSS and images only
Open Graph and Twitter Card metadata preview
Synchronized screenshots across all viewports
See all breakpoints simultaneously
Run 80+ WCAG checks and simulate disabilities
Verify across dozens of device presets
Full-page screenshots for client review
Check OG and Twitter Card metadata

AI development platform that builds production-ready full-stack apps with multi-agent collaboration