In modern web applications, the common way data is exchanged between client and server is through REST (representational state transfer) services. JSON is the standard file format for this two-way communication. In REST, the client makes a request to a specific endpoint, and the server responds to it.
gRPC uses Protobuf (Protocol Buffers) as the format for the payload and supports all kinds of streaming:
From a performance point of view, Protobuf is an efficient binary message format. Protobuf serialization results in small message payloads, which is important in limited-bandwidth scenarios like mobile and web apps.