gRPC vs REST: Choosing the best API design approach

TL;DR: Should I choose gRPC or REST?

Choose REST when simplicity, broad compatibility, and human readability are priorities for your application.

Key characteristics of REST

• Follows standard HTTP methods and status codes
• Stateless communications
• Resource-oriented architecture
• Human-readable payloads (typically JSON)
• Widely accepted across browsers and other platforms

Example REST endpoint response

{
  "message": "Hello, World!"
}

What is gRPC (gRPC Remote Procedure Call)?

gRPC is Google’s high-performance RPC framework.

Key characteristics of gRPC

• Built on HTTP/2 (multiplexing, server push, header compression)
• Uses Protocol Buffers for efficient binary serialization
• Strong typing through service definitions
• Bidirectional streaming support
• Code generation for multiple languages

Example gRPC service definition

service Greeter {
  rpc SayHello (HelloRequest) returns (HelloResponse) {}
}

Under the hood: gRPC and HTTP/2

One of gRPC’s most significant technical advantages is its use of HTTP/2 as a transport protocol. Understanding the technical details of HTTP/2 helps explain why gRPC offers substantial performance benefits.

Technical advantages for gRPC

• Efficient parsing
• Low overhead
• Reduced latency
• Multiplexing

Performance comparison

Serialization and payload size

| | REST | gRPC | |---------------------|------------------------------------|-----------------------------------------------| | Serialization | Uses text-based formats (JSON/XML) | Uses binary Protocol Buffers | | Payload size | Larger due to text encoding | Typically 30-40% smaller than JSON | | Serialization speed | Slower | Faster |

Network performance

• REST primarily uses HTTP/1.1
• gRPC is built on HTTP/2
• Multiplexing in gRPC reduces latency

Benchmarks

In typical scenarios, gRPC outperforms REST in several metrics:

• Throughput
• Latency
• CPU load
• Network utilization

Key advantages comparison

REST advantages over gRPC

• Full browser-level support
• Easy to learn and implement
• Large ecosystem and tooling
• Abundant libraries and middleware
• Extensive documentation
• Well-established security practices

gRPC Advantages Over REST

• Performance
• Strong contract definition
• Streaming capabilities
• Code generation
• Type safety across programming languages

When to choose REST

• Public APIs
• Browser-based applications
• Simple CRUD operations
• Microservices with diverse language needs
• Human-readable debugging

Example REST-based system

When to choose gRPC

• Microservices architecture
• Polyglot environments
• Real-time communication
• Low latency and high throughput systems
• IoT and mobile apps

Example gRPC-based system

Implementation examples

• REST implementation (Node.js/Express)
• gRPC implementation (Node.js)

Final verdict: REST or gRPC?

Here are key factors to consider for your project:

• Client requirements
• Decision flowchart
• Hybrid approaches
• Progressive migration
• Domain-based selection

Conclusion

Both API patterns have their place in modern software architecture. REST, with its simplicity and broad compatibility, remains the go-to choice for public APIs and browser-based applications.