gRPC is an open-source remote procedure call framework developed by Google. gRPC uses HTTP/2 as the transport and protocol buffers as the interface definition language and the message exchange format. A gRPC service, which is defined in a proto file, specifies the methods that can be called remotely and identifies the parameters and types for requests and responses.

gRPC provides protocol buffer compiler plug-ins in a variety of languages that may be used to generate server and client gRPC code, respectively.

A gRPC server application implements the methods and registers itself with a gRPC server to listen for and handle client requests. The channel on the gRPC server specifies the port that a gRPC client can use along with the host to connect to the gRPC server. The gRPC infrastructure in the gRPC server deserializes the request messages, invokes the implemented method logic, serializes the response message, and sends the message to the client.

A client contains a gRPC stub that mirrors the methods available on the server. The client makes RPC calls using the generated gRPC stubs, which sends the request to and receives the response from the gRPC server, serializing and deserializing the request and response messages.

gRPC is a self-referential acronym that stands for gRPC Remote Procedure Calls.