gRPC vs REST

gRPC and REST are the two dominant API communication protocols. Choosing the right one depends on your use case.

REST

• HTTP/1.1, JSON
• Human-readable
• Easy to debug
• Widely supported
• Stateless

GET /users/123
Content-Type: application/json

{ "id": 123, "name": "Alice" }

gRPC

• HTTP/2, Protocol Buffers (binary)
• Strongly typed schema (.proto files)
• 7-10x faster than REST
• Bidirectional streaming
• Code generation for all languages

service UserService {
  rpc GetUser (GetUserRequest) returns (User);
  rpc StreamUsers (Empty) returns (stream User);
}

message User {
  int32 id = 1;
  string name = 2;
}

Performance Comparison

Metric	REST (JSON)	gRPC (Protobuf)
Payload size	Larger	5-10x smaller
Serialization	Slow	Fast
HTTP version	HTTP/1.1	HTTP/2
Multiplexing	No	Yes

Streaming Types in gRPC

1. Unary: Single request, single response (like REST)
2. Server streaming: One request, stream of responses
3. Client streaming: Stream of requests, one response
4. Bidirectional: Both sides stream

When to Use

gRPC → Internal microservice communication
       Low latency requirements
       Streaming data
       Multiple languages

REST → Public APIs
       Browser clients
       Simple CRUD
       Third-party integrations

Conclusion

Use gRPC for internal high-performance service-to-service calls. Use REST for public APIs and browser-facing endpoints.