UtilityBaseDeveloper Tools
Code Playground
A live HTML, CSS & JS editor with instant preview, console, and shareable links.
Updated July 14, 2026
How to use the code playground
- 1Write HTML, CSS, and JavaScript in the three editor tabs.
- 2Watch the preview update live, or press Run.
- 3Read console.log output and errors in the console panel.
- 4Share a link, or download a standalone HTML file.
Common uses
- Testing a quick HTML/CSS/JS snippet
- Learning and experimenting with front-end code
- Prototyping a UI component or animation
- Sharing a reproducible bug or demo as a link
Frequently asked questions
How does the live preview work?
Your HTML, CSS, and JavaScript are combined into a single document and rendered in a sandboxed iframe. Whenever you edit (with auto-run on) it rebuilds and re-runs after a short pause, so the preview always reflects your latest code. You can also turn auto-run off and press Run manually — handy for heavier scripts you don't want re-executing on every keystroke.
Is it safe — where does my code run?
Everything runs locally in your browser. The preview is a sandboxed iframe with scripts allowed but no same-origin access, so your code can't read this page, its cookies, or your data, and nothing is ever uploaded to a server. The console panel only receives messages your own code sends via console.log, warnings, and errors.
Can I save or share what I make?
Two ways. Share copies a link that encodes your entire HTML, CSS, and JS into the URL, so anyone who opens it sees exactly your snippet — nothing is stored on a server. Or use the HTML button to download a single standalone .html file with everything inlined, which you can open in any browser or drop into a project.
About this tool
The code playground is a front-end editor that runs your HTML, CSS, and JavaScript live in the browser. Type in any of the three panes and the preview re-runs automatically; a built-in console captures your console.log output, warnings, and errors so you can debug without opening dev tools. Your code executes in a sandboxed iframe with no access to the page or your data, and nothing is uploaded — it all stays local. Start from an example, share a link that encodes your whole snippet for anyone to open, or download a standalone .html file. It's the fast way to test a snippet, learn front-end, prototype a UI idea, or hand someone a reproducible bug — free, no sign-up, no watermark.
Like most tools on UtilityBase, the code playground runs entirely in your browser — nothing you enter is uploaded or stored on a server. It's free to use with no account required. Browse more developer tools here.
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