Responsive Screen Tester
Preview an HTTPS website in nine phone, tablet and desktop viewport presets. Check layouts and find overflow on sites that allow embedding.
Some sites block embedding. If the preview is blank, open the page directly and use your browser’s responsive design mode.
Test a website at mobile, tablet and desktop widths
Enter an HTTPS page URL and click Load preview. Use Device to switch between presets. Start at Galaxy S23 (360 × 780) for a narrow layout, iPad Mini (768 × 1024) for tablet, and Laptop (1280 × 800) for desktop. On each size, check whether navigation wraps, text stays readable and the primary button fits.
When the preview is blank
The preview loads the page in a sandboxed iframe. Sites can refuse embedding with X-Frame-Options or a frame-ancestors policy. In that case, open the page directly and use your browser’s responsive design mode. For snippets, use the HTML Preview. For a broader review, use the Mobile-Friendly Checklist.
Frequently Asked Questions
Does the preview emulate the actual phone?
The presets change the frame’s CSS viewport dimensions. They do not emulate Safari, touch hardware, pixel density or network speed.Does ToolJiffy proxy the page?
Your browser requests the page directly. The destination sees that request, and sandbox restrictions can affect sign-in or other interactive features.