Developer tool · Free · No sign-up

HTML Previewer

Write HTML, CSS and JavaScript and see it render live.

Editor

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About this tool

This free online HTML previewer lets you write or paste HTML, CSS and JavaScript and instantly see how it renders in a large, resizable preview. Switch between mobile, tablet, laptop and desktop widths, set custom dimensions, view several screen sizes at once, or expand to full screen to test responsive layouts. The preview runs in a sandboxed iframe so you can experiment safely, and everything stays in your browser.

Key features

Live rendering

HTML, CSS and JS render instantly as you type.

Responsive testing

Device presets, custom width/height, multi-screen and full screen.

Safe sandbox

Runs in an isolated iframe so test code can't touch the page.

How to use it

1Type or paste your HTML (you can include <style> and <script> tags).
2The live preview updates automatically as you type.
3Pick a device size, enter custom dimensions, or use multi-screen view to test responsiveness.
4Click full screen for a distraction-free, large preview.
5Copy your markup or download it as an .html file when you're done.

Common use cases

Prototyping a component or layout quickly.
Testing how a snippet looks across screen sizes.
Teaching or learning front-end basics.

Frequently asked questions

Can I test responsive designs?

Yes. Choose mobile, tablet, laptop or desktop presets, enter exact custom width and height, view multiple screen sizes side by side, or expand the preview to full screen.

Can I use CSS and JavaScript too?

Yes. Add <style> tags for CSS and <script> tags for JavaScript directly in your HTML — both run in the live preview.

Is the preview safe and private?

The preview renders inside a sandboxed iframe isolated from this site, and your code never leaves your browser.

Private and free. Most of our tools run entirely in your browser, so the data you enter isn't uploaded or stored. There's no sign-up, and there never will be — they're built by the Fusion Trail Solutions team to be genuinely useful.