Blog
Tips for responsive design & developer tools
Page 1 of 12
Find and fix accessibility issues with Polypane
At Polypane, accessibility is one of the three core areas we focus on, along with performance and responsive design. If you're not familiar with Polypane, it's a web browser specifically for web developers. It has all…
The Intl API: The best browser API you're not using
Chances are you've used Moment.js , date-fns , Luxon , or numeral.js at some point. Developers have relied on these libraries for years to format dates, numbers, and currencies. Those are all very useful libraries…
How to debug the @starting-style at-rule in Polypane
The @starting-style at-rule makes it possible to animate in elements as you add them to the DOM, something that previously needed JavaScript trickery to achieve. In this article, we'll go over how to use @starting…
Polypane 28: Project improvements, Elements panel updates and Chromium 146
The first release of 2026 comes with plenty of improvements to Projects, the new Environments feature prevents you from confusing production for localhost, the Elements panel is faster and more powerful than ever, and…
Understanding the fundamentals of CSS Layout
When developers say that CSS is hard, they're usually talking about CSS layout. What often gets omitted though is that developers are assumed to understand and effectively use CSS without being taught how it works in the…
Not All Browser APIs Are "Web" APIs
When we talk about "the web platform", we often treat it as a unified, standards-based system: browsers implement features from the same specifications, even if they do so in different time frames. That should mean that…
Polypane 27.1: Expanding Portal
Polypane 27.1 is here and Polypane Portal has expanded! The Polypane console will now show the console messages from all connected browsers so you get instant feedback on errors and your own logs. Snippets are now also…
Polypane 27: Projects, a Snippets Panel and Chromium 142
Polypane 27 is out! This release brings a new project-focused workflow, a new snippets panel, improved DOM editing and is built on Chromium 142. Here's everything that's new in Polypane 27. Polypane Projects A project…
Using chrome-devtools-mcp with Polypane
The recently released chrome-devtools-mcp allows you to connect your coding agent (like GitHub Copilot) to a running Chromium instance to inspect and verify changes in the actual DOM. Thanks to changes made by the…
Polypane 26: Accurate device emulation with safe area and small viewport units
Polypane 26 brings the most accurate device emulation available anywhere. We now emulate small viewport units (svh) and device-specific safe area insets, two critical factors that affect every mobile layout but were…
CSS-only floating focus with anchor positioning
The Track focus debug tool in Polypane shows a floating outline that follows the keyboard focus around the page. This makes it easier to keep track of where the focus is and lets you determine (along with the focus…
Capturing screenshots in Polypane
Sharing in-progress work, pointing out a bug, or clarifying which area you're talking about: as a developer you're sharing screenshots all the time. In Polypane, we've made it easy to capture different types of…