HTML / CSS / JS Playground
Three editors, a live sandboxed preview and a console — share the whole thing as a link, no sign-up.
How to Use HTML / CSS / JS Playground in 3 Steps
Write
Type HTML, CSS and JavaScript in the three editors — Tab indents, Ctrl/⌘ + Enter runs. Drop an .html file onto the HTML editor to start from it.
Run and debug
The preview is a sandboxed iframe: your script cannot touch Toolity, cookies or storage. console.log, warnings, errors and uncaught exceptions appear in the console under the preview, with line numbers where the browser provides them.
Share or export
Download ▾ Share link (or Copy) gives a URL with the whole pen compressed into it — open it anywhere, no account. Download a single self-contained HTML file, or a ZIP with the three files separated.
HTML / CSS / JS Playground — Frequently Asked Questions
Where is my code saved?
Nowhere — Toolity has no server and this page uses no storage. The share link is the save: the three editors are compressed (deflate, via the browser’s CompressionStream) and base64-encoded into the URL fragment, which is never sent to any server. A typical pen is 1–3 KB of URL; browsers handle links up to about 60 KB.
How safe is the preview?
It runs in an iframe with sandbox="allow-scripts allow-modals allow-forms allow-popups" and no allow-same-origin, so the code gets a unique opaque origin: it cannot read Toolity’s cookies or localStorage, cannot navigate this page, and network requests are subject to the usual CORS rules.
Can I use libraries?
Yes — add a <script src="https://cdn.jsdelivr.net/npm/…"> or <link> tag in the HTML editor. Settings also offer one-click normalize.css and the Tailwind Play CDN. Modules work too: <script type="module"> with import from a CDN URL.
Why is there no syntax highlighting?
The editors are plain textareas so the page loads instantly and works offline with zero dependencies. Tab indenting, line counts and Ctrl/⌘ + Enter are there; a full editor would add ~300 KB. Paste from your IDE for anything long.
Does the console show everything?
console.log / info / warn / error / table (as JSON), uncaught errors and unhandled promise rejections are forwarded from the sandbox. Objects are printed as JSON (circular structures are flattened); DOM nodes print as their outerHTML.
Is my code uploaded anywhere?
No. Formatting and minifying run in JavaScript inside your browser tab. The formatter libraries are downloaded once from a CDN; your code never leaves the page.