gRPC is an acronym for Google Remote Procedure Call. It uses HTTP/2 protocol , however HTTP is not exposed to the API designer. The information is delivered using protobufs. The client here uses gRPC by having to decide which procedure to call and also uses the code generated stub to make a call and passes the expected parameter values. The client application communicates with the server on a different machine by directly making a method call like it were a local object.