The environment allows to make changes to a program at runtime, so variables and functions may be redefined and the changes take effect immediately.

A programmer can also create and schedule code for future execution, as well as data events such as notes and graphics objects.

Impromptu's Scheme interpreter was initially built from the TinyScheme 1.35 baseline, but it has been substantially modified since to better suit the live coding context.

This language is syntactically Scheme-like, but semantically closer to C, and is designed for real-time sound synthesis and other computationally heavy tasks.

A Study in Keith is a live coding performance in Impromptu by Andrew Sorensen.