What is gRPC

• Interface definition: .proto files describing service and messages
• Serialization: Protocol Buffers (binary, compact)
• Transport: HTTP/2 (multiplexing, bidirectional)
• Streaming: unary, server-streaming, client-streaming, bidirectional
• Client code generation for 10+ languages (Go, Java, Python, C++, Ruby, Node.js)

service UserService {
  rpc GetUser (GetUserRequest) returns (User);
  rpc ListUsers (Empty) returns (stream User);  // server-streaming
}

• Webhook
• HTTP/2
• JWT

When comparing gRPC and REST, performance and efficiency are critical factors to consider. gRPC, which uses HTTP/2 as its transport protocol, offers several advantages over REST, particularly in terms of speed and resource utilization.

One of the primary benefits of gRPC is its use of Protocol Buffers for serialization. This binary format is significantly more compact than JSON, which is commonly used in REST APIs. As a result, gRPC can achieve a 5-10× reduction in payload size, leading to faster transmission times and reduced bandwidth consumption.

Additionally, gRPC supports bidirectional streaming, allowing both the client and server to send data simultaneously. This feature is particularly useful in scenarios requiring real-time updates, such as chat applications or live data feeds, where REST would typically require multiple requests and responses.

In contrast, REST is built on HTTP/1.1 and primarily relies on the request-response model. While REST is easier to implement and more widely adopted, it often incurs higher latency and overhead due to its reliance on text-based formats and lack of built-in streaming capabilities.

In summary, for applications demanding high performance and efficient resource usage, gRPC is often the superior choice, especially in microservices architectures where service-to-service communication is prevalent.