RSRobince Studio

Online Code Editor

A free online code editor for HTML, CSS and JavaScript. Type in any of the three panels, press Run to see the result and open Console for JavaScript output. Tidy your code with the Format button. Nothing is uploaded, and your code is saved in your browser so it is still here when you come back.

Runs in your browser. Your files are never uploaded.

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How to use Online Code Editor

  1. Type or paste HTML in the HTML tab.
  2. Add styles in the CSS tab and behaviour in the JavaScript tab.
  3. Press Run (or Ctrl+Enter) to see the result; open Console for JavaScript output and errors.
  4. Use Format to tidy the code, or Reset to return to the starting code.

How the preview works

Your HTML, CSS and JavaScript are combined into a single page and shown in a sandboxed frame on the right. The preview updates when you press Run (or Ctrl+Enter), not on every keystroke, so it never reloads while you are in the middle of typing. Make your changes, run them, and see the effect.

Formatting your code

The Format button tidies the code in the tab you are editing — fixing indentation and spacing — using Prettier, the same formatter many professional editors use. If the code has a syntax error it is left as you typed it, so you can find and fix the problem first.

Using the console

Open the Console panel to see messages from your JavaScript. Use console.log() to print values while you work out why something is not behaving, and read the red error messages — they usually name the problem and the line. The console clears each time you run.

Good for learning

If you are learning web development, type the examples from a tutorial here and change them to see what each line does. Because the code stays in your browser, you can close the tab and your work is still here next time. Pair this editor with the HTML and CSS tutorials to practise as you read.

Why use this online code editor tool

  • Run when you are ready. The preview updates when you press Run (or Ctrl+Enter), so it never reloads mid-edit.
  • One-click formatting. The Format button tidies and indents your HTML, CSS or JavaScript using Prettier.
  • JavaScript console. console.log output and errors appear in a console panel, just like the browser dev tools.
  • Saved in your browser. Your code is kept in this browser between visits and is never sent to a server. No account, no limits.

Frequently asked questions

Is this online code editor free?

Yes, completely free with no sign-up. It runs entirely in your browser, so there is no server cost and nothing to pay.

Does it support JavaScript?

Yes. Code in the JavaScript tab runs in the live preview, and anything you log with console.log, along with any errors, appears in the Console panel.

Is my code uploaded anywhere?

No. The editor and preview run on your device. Your code is saved only in this browser (local storage) and is never uploaded.

Can I build and test a full web page here?

Yes, for front-end HTML, CSS and JavaScript. The preview is a sandboxed page, so features that need a server, cookies or cross-site requests may be limited. For learning and prototyping layouts, components and scripts it works well.

Can I run Python, C or Java?

Not yet — this editor runs the languages the browser itself understands: HTML, CSS and JavaScript. A Python editor that runs in the browser is planned.

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