How to use
- Paste HTML.
- Toggle widths or add a custom width.
- Allow scripts only if you trust the code.
Worked example
In the sample page, the header menu drops to a second line in the 360 and 390 px frames, and the feature cards switch from one column to three from 768 px.
Supported formats and limits
| Input | HTML (with inline or embedded CSS) |
|---|---|
| Output | Preview frames |
| Engine | Sandboxed srcdoc iframes scaled to fit |
Limitations
- Testing a live URL is not possible here because most sites block being framed; paste the HTML instead.
- Frames reproduce viewport width only, not a real device's browser, pixel density or touch behaviour.
Questions
Can I preview a live website by URL?
No. Most sites block being shown inside another page, so paste the HTML and CSS instead.
Is it the same as testing on a phone?
It matches the viewport width, which is what media queries respond to. It does not emulate a phone's browser engine, pixel density, touch input or on-screen keyboard, so check important pages on real devices too.
Do scripts in my HTML run?
Not by default: frames are sandboxed without scripts. You can allow scripts; they still cannot reach this page or its storage.
Privacy
Runs on your device. Files and text are processed in this browser tab and are not uploaded.
See the privacy policy for how toolsdocks handles data.