Varlink is an interface description format and protocol that aims to
make services accessible to both humans and machines in the simplest
feasible way.

A varlink interface combines the classic UNIX command line options,
STDIN/OUT/ERROR text formats, man pages, service metadata and provides
the equivalent over a single file descriptor, a.k.a. “FD3”.

Varlink is plain-text, type-safe, discoverable, self-documenting,
remotable, testable, easy to debug. Varlink is accessible from any
programming environment. See the Ideals page for more. And everybody
likes Screenshots.