Ypsilon is an implementation of the scheme programming language which conforms to the latest standard r6rs. it achieves a remarkably short garbage collection pause time and improved performance during parallel execution because it implements mostly concurrent garbage collection, which is optimized for the multi-core cpu system.

it implements the full features of r6rs and the r6rs standard libraries. it also features a built-in foreign function interface for integration with c, while maintaining a small package footprint.