Responsive Viewport Tester
Preview a website inside a frame at mobile, tablet or desktop width.
Quick answer: enter your details below and click Preview — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
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Developer
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How to use
- Type the website address.
- Choose Mobile, Tablet, Desktop or a custom pixel width.
- Click Preview and inspect the framed page at that width.
About this tool
Enter a website address and pick a width, and this tool renders the page inside a preview frame in the result area at that width, so you can see roughly how a layout behaves on a smaller screen. Widths cover mobile, tablet and desktop, plus a custom pixel width. Be aware that some sites block framing and will show a blank frame; that is the site's own framing policy, not a fault in the preview.
Frequently asked questions
Why is the frame blank for some sites?
Because those sites send framing protections that tell browsers not to display them inside another page. The preview cannot override that policy.
Does this replace testing on a real phone?
No. It is a rough layout check; real devices also differ in touch handling, fonts and network behaviour.