RunX runs a single file of front-end code the moment you paste it: a full HTML page, a React component, a Vue single-file component or plain JavaScript. It recognizes the type, loads the libraries the code imports, and turns on Tailwind when the code uses it. Handy for trying code from an AI chat, or for learning and testing HTML and CSS without creating files.
Paste a snippet into the editor, or start from an example. Your last code is kept in this browser.
The preview updates shortly after each change. Check it at phone and tablet widths, or open it in a new tab.
Errors appear in the console; copy them back into your AI chat. Share a link with the code, or download it as an HTML file.
Any npm package that runs in the browser: write the import as usual, for example from three or framer-motion, and it loads from the esm.sh CDN. React, Vue, three.js, d3 and gsap all work.
The code runs in a sandboxed frame with no access to this site, its storage or your logins. Links shared by others wait for you to press Run.
Nowhere. It is compressed into the link itself, after the # sign, which browsers never send to a server.
Plain HTML, CSS and JavaScript do. Imported libraries, Tailwind and JSX or Vue compilation need a network connection the first time.
Projects with several files, imports from your own folders (like @/components), Node.js APIs and server code. RunX is for one file at a time.