All 15 gRPC Services questions
More in gRPC Services
What is the purpose of the ServerCallContext parameter present in every gRPC server method, and what information does it expose? How do you define a gRPC service contract using Protocol Buffers (.proto files), and how does code generation work in a .NET project? How do you implement a gRPC server method in ASP.NET Core, and how does it integrate with the standard hosting model? What is gRPC-Web, and why is it needed for calling gRPC services directly from a browser-based JavaScript client? How do you implement server-streaming gRPC using C#'s IAsyncEnumerable<T> or IServerStreamWriter<T>? What is protobuf field numbering, and why must you never reuse or renumber a field once a message definition has shipped to production? How would you version a gRPC service's contract while maintaining backward compatibility with existing clients? How does client-side load balancing work for gRPC when calling a service with multiple backend instances, without a dedicated load balancer? What are the four types of gRPC service methods (unary, server streaming, client streaming, bidirectional streaming), and when is each appropriate? How does gRPC handle errors and status codes, and how does this differ from HTTP status codes in REST?
Advertisement
.NET › gRPC Services

What is gRPC, and how does it differ from a traditional REST/JSON API?

Beginner

Answer

gRPC is a high-performance RPC (Remote Procedure Call) framework built on HTTP/2, using Protocol Buffers (protobuf) as its binary serialization format for both requests and responses, rather than JSON over HTTP/1.1 as typical REST APIs use. This gives gRPC significantly smaller message sizes (binary vs text), lower latency, native support for streaming (client, server, and bidirectional), and strongly-typed contracts generated from a .proto file -- at the cost of being less human-readable and requiring more tooling than plain REST/JSON, and having limited direct browser support without a proxy layer (gRPC-Web).
// order.proto -- defines the contract
service OrderService {
  rpc GetOrder (GetOrderRequest) returns (OrderResponse);
}
message GetOrderRequest { int32 order_id = 1; }
message OrderResponse { int32 id = 1; string status = 2; }
Real-world example A microservices platform uses gRPC for internal service-to-service communication (where performance and strong typing matter most) while still exposing a REST/JSON API at the edge for external, browser-based clients, using each protocol where it's best suited.

Common follow-ups: Why is gRPC less suitable for direct browser consumption without gRPC-Web?;How does protobuf's binary format achieve smaller payloads than JSON?

ASP.NET Core Middleware & Request Pipeline;Microservices & Distributed Architecture Patterns
All 15 gRPC Services questions