Data Protocols Explained: REST, gRPC, GraphQL, JSON-RPC & WebSockets
To compare these five data protocols, it’s useful to think of them as different ways of “ordering food” from a restaurant. Some are simple one-time orders (REST), while others are like having a direct phone line to the kitchen (WebSockets).
Quick Comparison Table
| Protocol | Model | Primary Data Format | Connection Type | Best Use Case |
|---|---|---|---|---|
| REST | Resource-based | JSON / XML | Request-Response | Public APIs & Web Services |
| gRPC | Action-based | Binary (Protobuf) | Persistent (HTTP/2) | Fast Internal Microservices |
| GraphQL | Query-based | JSON | Request-Response | Complex Frontend UI Data |
| JSON-RPC | Action-based | JSON | Transport-agnostic | Blockchain & MCP Servers |
| WebSockets | Event-driven | Flexible (Text/Binary) | Full-Duplex (Live) | Real-time Chat & Gaming |
1. REST (Representational State Transfer)
The Concept: You treat everything as a “resource” (a noun) and use standard HTTP verbs (GET, POST, PUT, DELETE) to interact with it.
GET /books/123Practical Use Case: Building a public API for a blog or an e-commerce site where you want to fetch specific objects.
Why use it: It is the industry standard for web services because it is easy to cache and works in every browser.
2. gRPC (Google Remote Procedure Call)
The Concept: A high-performance, contract-based system. Instead of sending text-based JSON, it sends compact binary data using Protocol Buffers.
Service.GetBook(ID: 123)Practical Use Case: Communication between internal microservices at companies like Netflix or Spotify where speed is the #1 priority.
Why use it: It’s significantly faster than REST and handles bi-directional streaming natively.
3. GraphQL
The Concept: The client sends a specific “query” asking for exactly what it needs. This prevents “over-fetching” (getting 50 fields when you only need 2).
{ book(id: 123) { title, price } }Practical Use Case: A mobile app dashboard that needs to pull data from a database, an AI service, and a user profile all in one single request.
Why use it: It gives frontend developers total control over the shape of the data they receive.
4. JSON-RPC
The Concept: A very simple “Remote Procedure Call” protocol that uses JSON. It doesn’t care about “resources” like REST; it only cares about calling a function on the server.
{"method": "get_book", "params": [123], "id": 1}Practical Use Case: Interacting with Ethereum nodes or building Model Context Protocol (MCP) servers for AI tools.
Why use it: It is lightweight and works over any transport (HTTP, local files, or even serial ports).
5. WebSockets
The Concept: A persistent, two-way connection. Once the “handshake” is done, the server can push data to the client at any time without being asked.
socket.send("Hello!")
// Server can reply immediately, anytimePractical Use Case: Live chat apps (like Slack/Discord), multiplayer games, or live stock market tickers.
Why use it: It has the lowest latency for continuous real-time updates.
Choosing the Right Protocol
Here’s a mental model to help you pick:
| If you need… | Choose |
|---|---|
| A simple, cacheable public API | REST |
| Blazing-fast internal service communication | gRPC |
| Flexible queries with no over-fetching | GraphQL |
| Simple RPC over any transport layer | JSON-RPC |
| Real-time, bidirectional communication | WebSockets |
Final Thoughts
Each protocol has its sweet spot. REST remains king for public APIs due to its simplicity and ubiquity. gRPC dominates in performance-critical microservices. GraphQL shines when frontend teams need flexibility. JSON-RPC is the go-to for blockchain and emerging AI tool ecosystems. And WebSockets are unbeatable for anything real-time.
Understanding these protocols isn’t just about memorizing specs—it’s about knowing when and why to reach for each tool.
Happy building! 🚀