tags pointing to public CDNs. The sandboxed iframe will load them, so you can prototype with libraries like React, Vue, or D3."}},{"@type":"Question","name":"Is my code uploaded anywhere?","acceptedAnswer":{"@type":"Answer","text":"No. Everything runs in your browser. Your HTML, CSS, and JavaScript stay local — nothing is sent to JSONTech servers."}}]}

HTML Editor

Write HTML, CSS, and JS with a live preview — in-browser playground

Loading editor...

Preview

Prototype HTML, CSS, and JavaScript with an instant preview

When you're iterating on layout, animations, or a quick demo, jumping between an editor and a browser tab kills momentum. A live HTML playground lets you write markup, styles, and behavior in one place and see the result render side by side, with no install and no setup.

Use the editor when you need to

Reproduce a styling bug

Build a minimal repro in HTML, CSS, and JS to isolate a layout or scripting issue without your full app.

Try a quick UI idea

Sketch an interaction in the playground before deciding whether it's worth building in your real codebase.

Share a snippet with a teammate

Build a tiny demo, screenshot the output, and link the code back to the conversation.

How to use the HTML editor

1
Write HTML, CSS, and JavaScript in the corresponding tabs.
2
Watch the sandboxed preview update as you type.
3
Copy the combined snippet or download it as a single HTML file.

Keep going

Just preview HTML

Use the viewer when you only need to render existing markup, not edit it.

Format the result

Beautify or minify your snippet before pasting into your codebase.

Format CSS

Clean up extracted CSS for review or sharing.

Format JS

Pretty-print the JavaScript half of your snippet.

Common playground workflows

Build a CSS bug repro

Reduce a layout issue to the smallest possible HTML and CSS so you can fix or report it.

Test a JavaScript snippet

Run a small script against a custom DOM without scaffolding a project.

Demo an idea live

Open the playground in a screen share to show a teammate what you're describing.

Häufig gestellte Fragen

It's a focused playground for prototyping HTML, CSS, and JavaScript with a live sandboxed preview. It's ideal for quick experiments, bug repros, and demos — not for building full applications.

Yes. The preview runs inside an iframe with sandbox attributes, so scripts in the preview cannot affect the rest of the page or read data from outside the frame.

Use the download or copy buttons to export your snippet as a single HTML file. The combined output includes your CSS in a <style> tag and your JavaScript in a <script> tag.

Yes. You can include <script src="..."></script> tags pointing to public CDNs. The sandboxed iframe will load them, so you can prototype with libraries like React, Vue, or D3.

No. Everything runs in your browser. Your HTML, CSS, and JavaScript stay local — nothing is sent to JSONTech servers.