MuJS was designed with a focus on small size, correctness, and simplicity. It is written in portable C and implements ECMAScript as specified by ECMA-262. The interface for binding with native code is designed to be as simple as possible to use, and is very similar to Lua. There is no need to interact with byzantine C++ template mechanisms, or worry about marking and unmarking garbage collection roots, or wrestle with obscure build systems.
MuJS is developed and maintained by Artifex Software. It was originally developed for use with the MuPDF viewer, but is designed to be useful as an independent component.
The primary meeting place for the MuJS community is the #mupdf Discord channel.
MuJS is free open source software distributed under the ISC license.