Built for professional web developers who care about their craft.

The missing half of your development environment.

Polypane is a development browser where you build responsive, fast, accessible and SEO-friendly websites that work for everyone.
Used alongside your IDE to test, debug, and preview sites across screens, devices, and user needs.

Start Your Free Trial 14 day trial. No credit card needed.

Polypane showing six different panes in one overview, emulating different devices and viewports

Polypane showing the same site in light mode, dark mode, forced color mode and reduced motion. The emulation settings are open showing additional options.

Polypane showing a single site with its landmarks highlighted as well as a focus trail rendered across the page. An opened sidebar shows the heading structure of the page.

Polypane with an opened sidebar showing the meta information of a page: title, description as wel as og tags and other meta data. The top of a social media card preview for Bluesky is visible.

Polypane showing three panes, with a sidebar containing the element inspector. The H1 element that's selected is highlighted in all panes. The sidebar shows the CSS properties and box model of the selected element.

These companies use Polypane

Trusted by developers shipping work that matters.

This thing is FAST and the synchronized scrolling works amazingly. Prepare to be impressed.

Vivian Guillen Frontend Dev, Curator at Tailwind Weekly

Polypane is really saving my bacon. Kilian knocked it out of the park, this is my new favorite development tool.

Scott Tolinski Syntax.fm host, Level Up Tutorials

Polypane helped me see a spacing issue between two breakpoints that I wasn’t aware of. Love it 💯

Sara Soueidan Front-end UI engineer, Speaker/Trainer

I've started playing around with Polypane and 🤯. It has awesome debugging tools, I'm really impressed.

Kevin Powell CSS Evangelist

Build, don't browse.

Chrome, Firefox and Safari are excellent browsers for browsing the web. Polypane is the browser developers use for building websites. It's a Chromium-powered development browser with tools designed for building responsive, accessible, and high-quality sites.

See every breakpoint

Mobile to 5K. Every breakpoint visible and synchronized.

Catch issues as you build

Structure, metadata, accessibility. Instant feedback while you work.

View everything side by side

Dark mode, light mode, high contrast, reduced motion. All visible at once.

Beyond Chrome, Firefox and Safari

Why developers choose Polypane over Chrome, Firefox or Safari

Polypane replaces your patchwork of tools with a single, powerful browser designed for building better websites. Once you try it, you'll never want to go back.

Chrome, Firefox or Safari

Frustration. Inefficiency. Blind spots.

With Polypane

Clarity. Speed. Confidence.

Switching between breakpoints manually

Constantly resizing your window or dragging dev tools around.

Multiple synchronized viewports

See and interact with all breakpoints at once. Build once, preview everywhere.

Slow testing workflow

One screen, one viewport, one change at a time.

Faster iterations

Edit code → changes live across all devices instantly.

Missing accessibility issues

Limited or no built-in accessibility checks. Manual testing with patchwork extensions. Ship inaccessible code anyway.

Built-in accessibility auditing

Instant contrast checks, focus order overview, accessibility features emulation, and more.

Guessing about UX across devices

What your site actually looks like on mobile is a mystery until you test each one individually.

Device realism

Pre-configured panes that match real device resolutions and behaviors.

Over-reliance on extensions

Cramming 10+ dev tools into Chrome, Firefox or Safari and still missing insights.

All-in-one power tools

Meta previews, live reloading, image overlays, design & dev tools in one clean interface.

Inconsistent testing environments

You test on your screen. Designer tests on theirs. QA tests on something else. "Works on my machine" but everyone sees something else.

Unified testing experience

You all see the same thing: every pane, every breakpoint, every audit. Everyone's on the same page.