@zlepper/rpc

Allows RPC from the main thread to a background worker thread (Of any kind), using ES6 classes.

eureca

Nodejs remote procedure call built on top of sockjs (This package is deprecated please use eureca.io instead!)

rerpc

a simplified and flexible RPC system with unified model for client-to-server and server-to-server communication on top of HTTP and/or Socket.IO

json-api-schema

JSON Api Schema is a JSON dialect that can describe any Web Based API that uses JSON to exchange data.