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Free tool

Free HTML sandbox

Paste HTML, CSS, and JavaScript, press Run, and watch it execute in an isolated preview. No setup, no local server, nothing stored.

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Editor · HTML + CSS + JS
Result sandboxed frame · scripts isolated
✓Your page live in seconds ✓An unlisted link you can send anyone ✓Claim it free to keep it live

Runs entirely in your browser. Nothing you paste is stored until you choose to publish.

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What people run here

A safe place to try code you didn’t write yet, or didn’t write at all

An HTML sandbox is an isolated environment where you can run HTML, CSS, and JavaScript safely: the code executes inside a sandboxed browser frame that can’t touch your files, cookies, or the page around it. Paste your code above and press Run to see the result instantly.

Check AI-generated code

ChatGPT or Claude handed you a block of HTML? Run it here before you trust it, and see exactly what it renders and what its scripts do, isolated from everything else.

An HTML and CSS sandbox for layout

Try a grid, an animation, a one-off style fix. The sandbox renders a full document, so what works here works in a real browser tab.

Test JS snippets safely

Event handlers, DOM manipulation, little widgets: scripts execute inside the isolated frame, with no access to your cookies, files, or this page.

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sandbox:/index.html

What sandbox:/index.html means, and how to open it

When an AI assistant such as ChatGPT or Claude runs code for you, it writes files into its own sandbox and may show a path like sandbox:/index.html, sandbox:/quiz.html or sandbox:/downloads/index.html. That path points into the virtual file system inside the AI’s sandbox, a private, temporary workspace tied to that chat. The file is not on the web, so the link stops working outside the chat: in a new tab, on another device, or in a message to someone else. There are two ways out. Copy the HTML into the HTML sandbox above and press Run to see it work, or publish it to a real link with the box on this page so it opens in any browser.
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The next step

When the experiment works, ship it as a real page

A sandbox is for finding out whether the code works. The moment it does, you usually need a link, for a client, a teammate, or your own phone. Pagelive turns the same HTML into a live page: noindex by default, optionally password-protected, with opens and time-on-page tracking built in. You can even publish straight from Claude.

Turn it into a URL

Convert the working code into a clean, shareable Pagelive link in one step. Free, no signup.

HTML to URL → →

Host it properly

Publish with view analytics, version history, and optional passwords: a link that reports back when it’s opened.

Publish HTML → →

Grow it into a website

Going past one experiment? Take the same HTML to a full site: your structure, your domain.

HTML to website → →
Free for 2 public pages · Solo is $15/mo or $150/yr →
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HTML sandbox FAQ

It is a file path inside an AI assistant’s sandbox, the temporary workspace where a tool such as ChatGPT or Claude writes files while it runs code for you. The sandbox:/ part means the file lives in that virtual file system, not on the internet. You can see it inside the chat, but nobody can open it as a web page.

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From sandbox to a live link.

Drop the working HTML and get a shareable, tracked URL in seconds. Free, no signup, noindex by default.