Can you describe how you designed and implemented REST and gRPC APIs for internal and external platform services?

When designing REST and gRPC APIs for internal and external platform services, I based my approach on separation of responsibilities and requirements for performance and ease of integration.

For REST API:

• Used clear resource-oriented design with understandable URLs and HTTP methods (GET, POST, PUT, DELETE).
• Applied JSON standards for data exchange, ensuring validation and error handling with understandable status codes.
• For external services, added authentication (e.g., OAuth2 or JWT) and rate limiting.

For gRPC API:

• Defined services and methods in protobuf with clear message types.
• Used gRPC for high-performance communication between internal services, where speed and binary protocol are important.
• Implemented streaming where large data transfer or persistent connection is needed.

Example of a simple gRPC service in Go:

syntax = "proto3";

service UserService {
  rpc GetUser (UserRequest) returns (UserResponse);
}

message UserRequest {
  string user_id = 1;
}

message UserResponse {
  string name = 1;
  string email = 2;
}

In Go, I implement a server with a GetUser handler that receives user_id and returns user data.

This approach allows using REST for external clients with a convenient and understandable interface, and gRPC for internal services with high performance and strict typing.