What are the differences between RPC and RESTful API? When should you choose RPC?

RPC and RESTful API are two common communication methods for distributed systems, each with their own advantages and disadvantages:

RPC (Remote Procedure Call) Characteristics:

Advantages:

1. High Performance: Uses binary serialization (like Protobuf), high transmission efficiency
2. Strong Typing: Defines service contracts through IDL (Interface Definition Language), compile-time checking
3. Low Latency: Supports HTTP/2 multiplexing, reduces connection overhead
4. Bidirectional Streaming: Supports bidirectional streaming communication, suitable for real-time scenarios
5. Code Generation: Automatically generates client and server code, reduces development effort

Disadvantages:

1. Difficult Debugging: Binary protocols are not easy to view and debug directly
2. Learning Curve: Need to learn specific RPC frameworks and protocols
3. Browser Compatibility: Some RPC protocols (like gRPC) require additional support
4. High Coupling: Client and server need to share interface definitions

RESTful API Characteristics:

Advantages:

1. Simple to Use: Based on HTTP protocol, uses JSON/XML format
2. Strong Universality: Cross-platform, cross-language, native browser support
3. Easy Debugging: Can use curl, Postman and other tools to test directly
4. Loose Coupling: Client and server interact through URLs and HTTP methods
5. Cache Friendly: Leverages HTTP caching mechanisms to improve performance

Disadvantages:

1. Lower Performance: Text format (JSON) transmission efficiency is not as good as binary
2. Redundant Data: Each request contains HTTP headers, increasing transmission overhead
3. Stateless: Requires additional mechanisms to maintain session state
4. Poor Real-time Performance: Not suitable for scenarios requiring real-time bidirectional communication

Selection Recommendations:

• Internal Microservice Communication: Prioritize RPC (like gRPC, Dubbo)
• External APIs: Prioritize RESTful API
• Real-time Communication Scenarios: Choose RPC frameworks that support streaming
• Cross-language Team Collaboration: Consider the universality of RESTful API
• Performance-sensitive Scenarios: Choose RPC for better performance