Kerf vs. Polypane.
Kerf and Polypane solve different problems. The right pick depends on where you spend your day — shipping a codebase, or testing a design across screen sizes.
At a glance
Both Kerf and Polypane offer:
- Live style tweaking — change CSS and see it immediately as you work.
- Accessibility checks — catch contrast and hierarchy issues as you work (Pro in Kerf).
Kerf is better for
- Working on your source files. Kerf is a file-aware editor, not a browser.
It opens your local folder and writes directly to your
.cssand.htmlfiles. - Shipping. Kerf Pro includes one-click Vercel deploy. You go from local folder to live URL without touching a CLI or Git.
- System maintenance. Kerf scans your CSS for repeated values; Kerf Pro consolidates them into design tokens.
- Lower price. Kerf's core editor is free; Pro is $96/year or $10/mo, which comes in under Polypane's individual plan.
Polypane is better for
- Responsive testing. Polypane shows your site across many synchronized viewports at once. If your main job is checking a design at every width, it's the specialist tool.
- Browser-first workflows. Polypane is a specialized browser. It shows how your site behaves in the wild — social previews, interaction testing, media-query debugging.
- Depth of audit. Polypane's debug toolkit — color-blindness simulators, layout-shift overlay, structured data preview — covers more ground than Kerf's five-category audit.
Feature comparison
| Feature | Kerf | Polypane |
|---|---|---|
| Works on your source files | Yes — HTML, CSS, new files | No — edits the live DOM, not your files |
| Multi-viewport sync | Single focus | Extensive, simultaneous |
| One-click Vercel deploy | Yes (Pro) | No |
| Design token consolidation | Yes (Pro) | No |
| Accessibility audit | Five-category audit (Pro) | Extensive |
| Platforms | macOS, Linux (Windows coming soon) | macOS, Windows, Linux |
Pricing
Kerf
- Free tier: full visual editor.
- Pro: $96/year, $10/mo, or $149 lifetime.
- Pro adds Vercel deploy, design token consolidation, the accessibility audit, a snippet library, and a React Native editor.
Polypane
- Individual: ~$13/mo annual, ~$19/mo monthly.
- No free tier — subscription only.
- Verify current pricing at polypane.app/pricing.
Which one to pick
Pick Polypane if your day is dominated by responsive testing across devices. If you need an iPhone SE, an iPad, and a 4K monitor side by side, Polypane is worth the subscription.
Pick Kerf if the work is editing and shipping a static site's source: it writes to your files directly, consolidates your CSS into tokens, and deploys the folder to Vercel.