arpc is very much in alpha, very undocumented, and probably broken in many ways including only supporting python sync/async and TS outputs. Do not use in production yet!
arpc is a framework to build RPC API's cleanly. It is heavily CLI driven, and intends to build on top of the Next framework by adding cross platform client support.
To begin, you can call npx arpc init in a Next project. There are a lot of other commands within the CLI. Documentation pending!