Protocol Buffers & HTTP/2
JSON is human-readable, but it is slow to parse and bulky to transmit. For internal microservice communication, seconds matter. gRPC (Google Remote Procedure Call) runs over HTTP/2 and uses **Protocol Buffers** (Protobuf), a binary serialization format.
Performance Gains
Protobuf messages are typically 30-50% smaller than equivalent JSON. Parsing is an order of magnitude faster because the data is structured binary, not text. HTTP/2 adds multiplexing, allowing thousands of parallel requests over a single TCP connection.
The Code Generation Advantage
With gRPC, you define your service in a `.proto` file:
service PaymentService {
rpc ProcessPayment (PaymentRequest) returns (PaymentResponse);
}
The compiler then generates strongly-typed clients in Go, Java, Python, or Ruby. If you change a field type, the client code won't compile. This eliminates an entire class of 'integration bugs' caused by typos or type mismatches.
Conclusion
For public APIs, stick to REST/JSON for compatibility. For internal, high-throughput microservices, gRPC is the clear winner.