API Protocols Comparison

REST vs gRPC vs JSON-RPC: A Comprehensive Guide

Core Concepts at a Glance

Three distinct approaches for building APIs that allow different software systems to communicate, each with unique philosophies and use cases.

REST

An architectural style that leverages standard HTTP methods to act on "resources" identified by URLs. Communication is stateless and commonly uses JSON.

GET /users/123
Think: Interacting with nouns (resources)

gRPC

A modern, high-performance RPC framework using Protocol Buffers over HTTP/2, enabling bidirectional streaming and multiplexing.

UserService.GetUser({user_id: 123})
Think: Executing verbs (functions)

JSON-RPC

A lightweight RPC protocol using JSON that's transport-agnostic, running over HTTP, WebSockets, or other channels.

{"jsonrpc": "2.0", "method": "getUser", "params": {"userId": 123}, "id": 1}
Think: Simple method calls

Detailed Protocol Comparison

Feature REST gRPC JSON-RPC
Data Format JSON (text), XML Protocol Buffers (binary) JSON (text)
Transport HTTP/1.1 HTTP/2 HTTP, WebSocket, TCP
Model Resource/verb mapping RPC, method calls RPC, method calls
Streaming Support ❌ No ✅ Full duplex ⚠️ Via WebSocket
Typing Dynamic Strongly typed (IDL) Dynamic
Code Generation Limited, 3rd party Native, multi-language Available but basic
Readability ✅ Human-readable ❌ Binary ✅ Human-readable
Browser Support ✅ Mature, native ❌ Limited, via proxies ✅ Mature
Debugging ✅ Easy (JSON) ⚠️ Harder (binary) ✅ Easy (JSON)
Performance
⭐⭐ Moderate
⭐⭐⭐ High
⭐⭐ Moderate to High

When to Use Each Protocol

Use REST For

  • Public-facing APIs: Third-party developer consumption
  • Resource-centric services: CRUD operations on entities
  • Web & mobile backends: Quick API development
  • Browser compatibility: Native HTTP support

Best Practices:

  • • Use standard HTTP verbs correctly
  • • Implement proper status codes
  • • Version your API (/api/v1/)
  • • Use OpenAPI/Swagger documentation

Use gRPC For

  • Internal microservices: High-performance communication
  • Real-time streaming: Bidirectional data flow
  • Polyglot environments: Multi-language services
  • Network-constrained: Mobile/IoT applications

Best Practices:

  • • Design .proto contracts carefully
  • • Use deadlines and cancellation
  • • Implement health checks
  • • Use interceptors for cross-cutting concerns

Use JSON-RPC For

  • Simple procedure calls: Lightweight RPC
  • Blockchain applications: Ethereum node interaction
  • WebSocket commands: Real-time notifications
  • Transport flexibility: Multiple protocols

Best Practices:

  • • Follow JSON-RPC 2.0 specification
  • • Use id field for correlation
  • • Implement standard error objects
  • • Leverage batch requests

Frameworks & Development Tools

REST Frameworks

Python

  • • FastAPI
  • • Django REST Framework
  • • Flask

JavaScript/Node.js

  • • Express.js
  • • NestJS
  • • Koa

Java

  • • Spring Boot
  • • Jakarta EE (JAX-RS)

Go

  • • Gin
  • • Echo
  • • net/http

gRPC Frameworks

Python

  • • grpcio
  • • grpcio-tools

JavaScript/Node.js

  • • @grpc/grpc-js
  • • @grpc/proto-loader

Java

  • • grpc-java
  • • grpc-spring-boot-starter

Go

  • • grpc-go
  • • protoc-gen-go

JSON-RPC Frameworks

Python

  • • jsonrpcserver
  • • tinyrpc

JavaScript/Node.js

  • • json-rpc-2.0
  • • open-rpc

Java

  • • json-rpc-2.0-base

Go

  • • net/rpc/jsonrpc (stdlib)

Testing & Debugging Tools

REST Testing

  • • Postman
  • • Insomnia
  • • curl
  • • OpenAPI/Swagger UI

gRPC Testing

  • • BloomRPC
  • • Kreya
  • • grpcurl
  • • Postman (gRPC support)

JSON-RPC Testing

  • • Postman
  • • Insomnia
  • • curl
  • • Custom scripts

Performance Analysis

REST Performance

Moderate performance, limited by text parsing and HTTP/1.1 overhead. Higher latency at scale.

gRPC Performance

7-10x faster than REST+JSON. Supports multiplexed connections and streaming.

JSON-RPC Performance

Slightly faster than REST for batch calls. Lower latency with WebSockets.