phosphorus runs your Scratch projects really fast by compiling them to JavaScript. Try it out by pasting a URL or project ID into the field below or choosing an example.

Turbo Mode
An internal error occurred. Click here to file a bug report.

Package this project

Get a link to a web page that automatically runs your project.


Embed this project

Include the phosphorus player in your web site.

Report a problem

phosphorus is still in development. Click here to report a problem with this project.


phosphorus was created by Nathan. Its CPS-style compilation and overall design was inspired by Rhys's sb2.js. It would have more bugs if not for Truman and Tim. It uses the JSZip library, created by Stuart Knightley, David Duponchel, Franz Buchinger, and António Afonso, to read .sb2 files and compressed projects, and the canvg library, created by Gabe Lerner, to render SVGs in <canvas> elements.


The source code for phosphorus is available on GitHub.