What is the difference between gRPC and GraphQL?
Answer
gRPC and GraphQL solve different problems. gRPC is a high-performance RPC framework for service-to-service communication, optimized for internal microservice calls with strict contracts, binary serialization, and streaming. GraphQL is a query language and API protocol for client-to-server communication, allowing clients to request exactly the data they need, reducing over-fetching/under-fetching. Key differences: (1) Data fetching — GraphQL clients specify exactly which fields they want; gRPC returns the full message defined in the proto; (2) Transport — GraphQL runs over HTTP/1.1 with JSON; gRPC uses HTTP/2 with Protobuf; (3) Use case — GraphQL excels for flexible frontend APIs (BFF pattern); gRPC excels for backend microservices; (4) Schema — GraphQL has its own SDL; gRPC uses Protobuf; (5) Streaming — gRPC has native streaming; GraphQL Subscriptions use WebSockets. Many architectures use both: GraphQL for public APIs, gRPC for internal services.