# Best responsive testing tools

> The best responsive design testing tools in 2026, checked October 28: Chrome DevTools, Sitepeel, Responsively App, Responsive Viewer, Polypane and BrowserStack.

Canonical page: https://sitepeel.dev/compare/best-responsive-testing-tools/

Ten ways to see your site on phones, tablets and laptops, from free and built in to real devices in the cloud.

Published: 2026-10-28

Facts and prices checked: 2026-10-28

Tool used in this guide: [Responsive viewer extension](https://sitepeel.dev/responsive-viewer-chrome-extension/index.md)

Free website tool for this task: [Responsive checker](https://sitepeel.dev/free-tools/responsive-checker/index.md) (https://sitepeel.dev/free-tools/responsive-checker/)

## In short

- Free and already in your browser: Chrome DevTools device mode
- Every size at once from a link, with problems listed: Sitepeel
- A free desktop browser for it: Responsively App
- Paid, in depth: Polypane. Real phones: BrowserStack

## Free tools to test websites on different screen sizes

The best responsive design testing tools in 2026 are Chrome DevTools device mode, free and built in, Sitepeel’s free responsive checker for every screen size at once from a link, Responsively App for a free desktop browser, and Polypane for paid, in-depth testing. For real phones, use BrowserStack.

Responsive testing tools compared

| Tool | Best for | Price | Works in |
| --- | --- | --- | --- |
| Sitepeel | Every size at once, problems listed | Free, no sign-in | Chrome extension and web |
| Chrome DevTools | One size at a time, built in | Free | Chrome, Edge |
| Responsively App | A free desktop browser for it | Free, open source | macOS, Windows, Linux |
| Polypane | In-depth testing, paid | 14-day trial; from $9 a month | macOS, Windows, Linux |
| Responsive Viewer | Many screens in a Chrome tab | Free with ads; Pro $4.99 a month | Chrome |
| Am I Responsive | A four-device picture to share | Free | Web |
| BrowserStack | Real phones and browsers | Free trial; from $12.50 a month | Web |
| Mobile simulator | Phone frames in your browser | Free with ads; from $5.90 a month | Chrome, Firefox, Edge |
| Window Resizer | Resizing the window to a preset | Free | Chrome |
| Sizzy | A paid browser with synced devices | $15 a month or $499 once | macOS, Windows, Linux |

Good to know: Checked on October 28, 2026 on each product’s own site and store page. “No” means we couldn’t find it there. We make Sitepeel.

## Which responsive tester finds layout problems?

What each one does

| Feature | Sitepeel | Responsively App | Responsive Viewer | Polypane | Am I Responsive |
| --- | --- | --- | --- | --- | --- |
| From a link, nothing to install | Yes | No | Partly, a limited web preview | No | Yes |
| Several sizes side by side | Yes, up to 12 | Yes | Yes | Yes | Yes, four fixed sizes |
| Synced scrolling | Yes | Yes | Yes | Yes | No |
| Lists layout problems | Yes | No | No | Yes | No |
| Screenshots of every size | Yes, in the extension | Yes | Partly | Yes | Partly |
| Pages behind a login | Yes, in the extension | Yes | Yes | Yes | No |
| Real phones, not emulation | No | No | No | Partly | No |
| Free | Yes | Yes | Yes, with ads | No, 14-day trial | Yes |

## 1. Sitepeel

Paste a link to see the page on up to 12 phones, tablets, laptops and monitors side by side, in real device frames with synced scrolling. It lists layout problems: content wider than the screen, tiny text and small tap targets.

![Sitepeel responsive checker: linear.app on a monitor, laptop, tablet and phones, with layout problems listed](https://sitepeel.dev/images/compare/sitepeel-responsive.webp)

Sitepeel’s free responsive checker on linear.app.

- Pick it for a quick check you can share
- The free tool sees public pages; the Chrome extension works behind a login

## 2. Chrome DevTools

Device mode is already in Chrome: press Ctrl+Shift+M (Cmd+Shift+M on a Mac) in DevTools to pick a phone or drag to any width. It works on localhost and signed-in pages, one size at a time.

![Chrome for Developers: “Simulate mobile devices with device mode”](https://sitepeel.dev/images/compare/devtools-device-mode.webp)

Chrome’s device mode docs on October 28, 2026.

- Pick it for quick checks while you code
- No side-by-side view and no layout warnings

## 3. Responsively App

A free, open-source desktop browser that shows a site on many devices at once and mirrors your clicks, scrolls and navigation across them, with screenshots of every device and an MCP server for AI agents.

![Responsively App: free and open source, 25,496 stars, Download Now](https://sitepeel.dev/images/compare/responsively-home-1028.webp)

Responsively App on October 28, 2026.

- Pick it for daily work on your own site
- A desktop install; version 2.0 is in beta

- [Polypane vs Responsively App](https://sitepeel.dev/compare/polypane-vs-responsively/index.md)

## 4. Polypane

A paid browser for developers with synced panes at every breakpoint, accessibility and SEO checks, and an overflow detector that points to the element that breaks the layout. Free for students through GitHub’s Student Pack.

![Polypane: “See every screen, device and user preference, while you build”](https://sitepeel.dev/images/compare/polypane-home-1028.webp)

Polypane on October 28, 2026.

- Pick it if testing is a big part of your job

## Which one should you pick?

**Verdict:** Start with Chrome DevTools. To see every size at once and get problems listed, use Sitepeel. For a free desktop app, Responsively. For daily, in-depth work, Polypane. For real phones, BrowserStack.

## Questions and answers

### How do I test my website on different screen sizes for free?

Paste the link into Sitepeel’s free responsive checker to see it on up to 12 devices at once, or open Chrome DevTools device mode. Responsively App is a free desktop option.

### How do I test responsiveness in Chrome?

Open DevTools (F12), then press Ctrl+Shift+M, or Cmd+Shift+M on a Mac, to turn on device mode. Pick a phone from the list or drag the edges to any width.

### Do I need real devices to test responsive design?

Not for layout: emulated sizes show how the page reflows. Real phones matter for touch, speed and browser quirks; BrowserStack rents them by the month.

### Is Polypane free?

No. It has a 14-day trial with no card, then costs from $9 a month billed yearly. It’s free for students through the GitHub Student Developer Pack.

### Is Responsively App free?

Yes. Responsively App is free and open source for macOS, Windows and Linux.

## Further reading

- [Chrome DevTools: device mode](https://developer.chrome.com/docs/devtools/device-mode)
- [Responsively App](https://responsively.app/)
- [Responsive Viewer](https://responsiveviewer.org/)
- [Polypane: pricing](https://polypane.app/pricing/)
- [Am I Responsive](https://fireship.dev/amiresponsive)
- [BrowserStack: pricing](https://www.browserstack.com/pricing)
- [Mobile simulator (Mobile FIRST)](https://www.webmobilefirst.com/en/)
- [Sizzy](https://sizzy.co/)

## Related pages

- [Check a site on every screen size](https://sitepeel.dev/guides/check-website-on-every-screen-size/index.md): See a website on phones, tablets, laptops and monitors side by side, free. Find overflow, tiny text and small tap targets, then test real devices.
- [Responsive Viewer alternatives](https://sitepeel.dev/compare/responsive-viewer-alternatives/index.md): Responsive Viewer alternatives, checked October 2026: Sitepeel, Responsively App, Window Resizer, Polypane and DevTools. Free and paid ways to test screens.
- [Polypane alternatives](https://sitepeel.dev/compare/polypane-alternatives/index.md): Polypane alternatives, checked October 2026: Responsively App, Sizzy, Blisk, Responsive Viewer and Sitepeel’s free responsive checker, with prices and limits.
- [Polypane vs Responsively](https://sitepeel.dev/compare/polypane-vs-responsively/index.md): Polypane vs Responsively App, checked October 2026: devices, testing tools, AI agents, platforms and price. Plus a free way to check screens with no install.