switch theme


forkphorus runs Scratch 3, 2, and 1 projects really fast by compiling them to JavaScript. Try it out by pasting a project ID or URL into the field below, selecting a project file, dropping a file on the page, or exploring the examples studio.

The future of unshared projects

May 8, 2022 - The future of viewing unshared projects in forkphorus is currently unknown due to upcoming changes to the Scratch API. More information.

Report a problem

forkphorus is still in development. Click here to report a problem with this project. You can also comment problems here if you don't have a GitHub account.

Embed this project

Include the forkphorus player in your web site.


Package this project

Get a link to a web page that automatically runs your project. To package to HTML, EXE, APK, or other formats, use the HTML packager.

Package ×


Changes are applied automatically.

Advanced Settings

Help test unfinished features. These require a refresh to apply. Please read this first.

Try out TurboWarp

TurboWarp typically has better performance and compatibility than forkphorus and has an editor. Give it a try, you might like it.


forkphorus is maintained by GarboMuffin and other contributors. It is a fork of Nathan's phosphorus. Its CPS-style compilation was inspired by Rhys's sb2.js. The JSZip library is used to read .sb2 and .sb3 files. The canvg library is used to render SVGs for Scratch 2 projects. The scratch-sb1-converter library is used to support Scratch 1 projects. The cloud variable server is hosted by fosshost.org.


The source code for forkphorus is available on GitHub.