Testing responsive design across devices is essential for modern web development. This tool lets you preview any website in an iframe at common viewport sizes — mobile, tablet, and desktop — without needing multiple devices.

Note: Some websites block iframe embedding via X-Frame-Options or Content-Security-Policy headers. If a site doesn't load in the preview, it has blocked embedding. Everything runs in your browser.

Preview

Results

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How to Use

  1. Enter the website URL to preview
  2. Select the viewport size
  3. Click Calculate to load the preview
  4. Note: Some sites block iframe embedding

FAQ

Why doesn't the preview load for some sites?

Many websites set X-Frame-Options: DENY or Content-Security-Policy frame-ancestors to prevent embedding in iframes. This is a security feature.

Is this the same as browser DevTools?

Browser DevTools provides more accurate responsive testing with device emulation, touch simulation, and network throttling. This tool offers a quick visual check.

Is my data safe when I use Responsive Preview Tool?

Yes. All calculations run entirely in your browser. Your data is never sent to a server, stored in a database, or shared with anyone. You can use this tool with complete confidence that your information remains private.

Learn More

Guides that feature this tool