MuJS is a lightweight Javascript interpreter designed for embedding in other software to extend them with scripting capabilities. It is written in portable C and implements ECMAScript as specified by ECMA-262.

Why? Because V8, SpiderMonkey and JavaScriptCore are all too big and complex. MuJS's focus is on small size, correctness and simplicity.

The interface for binding with native code is designed to be as simple as possible to use, and is similar to Lua. There is no need for interacting with byzantine C++ template mechanisms, or worry about marking and unmarking garbage collection roots, or wrestle with obscure build systems.


MuJS is Copyright 2014 Artifex Software, Inc.

This program is free software: you can redistribute it and/or modify it under the terms of the Affero GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

For commercial licensing please contact



The latest development source is available directly from the git repository:

git clone git://

Or browse the source online.