Utility Tools

Responsive Design Tester

Free online Responsive Design Tester tool. Process data securely and privately offline in your browser.

Utility ToolsAll Tools

⚙️ Responsive Design Tester Controls

✨ Output & Results

Ready

🔒 Total Privacy: All processing is done locally in your browser. No data is sent to external servers.

Responsive Design Tester

Test your website on multiple device screen sizes simultaneously. Our free Responsive Tester renders your layouts in precise viewports locally, ensuring your UI code remains private.

What is the Responsive Design Tester?

Modern web design requires ensuring your layout looks perfect on a massive 4K desktop monitor and a tiny 320px mobile screen simultaneously. Constantly resizing your browser window is tedious and inaccurate. The Responsive Design Tester solves this by using HTML `iframes` to render your website across multiple exact device dimensions (e.g., iPhone 14, iPad Pro, 1080p Desktop) all on one screen. Because you are testing proprietary, unreleased staging URLs, this tool relies entirely on local browser rendering. We do not track your URLs or log your design assets.

Why Use Our Responsive Design Tester?

  • Exact Pixel Dimensions: Tests your CSS media queries against accurate device sizes.
  • Simultaneous Views: See desktop, tablet, and mobile views side-by-side.
  • 100% Secure: Local iframe rendering means you can safely test internal 'localhost' projects.
  • Instant Refresh: Make a CSS change locally and see it reflect across all devices instantly.

How to Use the Responsive Design Tester

1.

Enter the URL of your staging or live website.

2.

Click 'Load Viewports'.

3.

Scroll down to see your website rendered within various device frames.

4.

Interact with the iframes to test mobile navigation menus and touch targets.

Frequently Asked Questions

Why does my site refuse to load in the tester?

If your website's server has the `X-Frame-Options` security header set to `DENY` or `SAMEORIGIN`, modern browsers will physically block it from rendering inside our iframes.

Can I test my local React or Vite project?

Yes! Because the rendering happens entirely in your browser, you can enter `http://localhost:3000` and it will work perfectly.

Are my staging URLs tracked?

Absolutely not. We prioritize developer privacy.

Privacy Note

All file processing is performed locally in your web browser. We do not upload, store, or view your data.