What does gRPC primarily utilize to facilitate remote procedure calls?

gRPC primarily utilizes HTTP/2 and protocol buffers to facilitate remote procedure calls. The use of HTTP/2 allows gRPC to take advantage of features like multiplexing and flow control, which enhance performance over the traditional HTTP/1.1 used in many other protocols. This enables multiple concurrent calls over a single connection, reducing latency and improving efficiency.

Protocol buffers, a language-agnostic binary serialization format, are employed by gRPC for defining service interfaces and for serializing structured data. They are more efficient than text-based formats like JSON or XML, both in terms of serialization/deserialization speed and size, leading to faster performance and reduced network bandwidth consumption.

Adopting these technologies allows gRPC to support bi-directional streaming, asynchronous messaging, and a variety of programming languages, making it a powerful solution for modern microservices architecture.