Chibi-Scheme is a very small library intended for use as an extension and scripting language in C programs. In addition to support for lightweight VM-based threads, each VM itself runs in an isolated heap allowing multiple VMs to run simultaneously in different OS threads.

The default language is R7RS Scheme, with support for all libraries. Support for additional languages such as JavaScript, Go, Lua and Bash are planned for future releases. Scheme is chosen as a substrate because its first class continuations and guaranteed tail-call optimization makes implementing other languages easy.

Chibi-Scheme is known to work on 32 and 64-bit Linux, FreeBSD and OS X, Plan9, Windows (using Cygwin), iOS, and Emscripten.

The project home is at and mailing list at

Download version 0.10.0 or browse the manual online at