Node.js Microservices

Below is a clear, beginner-friendly Node.js Microservices guide, structured like a complete tutorial that you can use for learning or documentation.

🚀 Node.js Microservices Tutorial

Microservices architecture is a way of building applications as a collection of small, independent services, each responsible for a specific functionality. Node.js is widely used for microservices because of its lightweight, fast, and scalable nature.

✅ What Are Microservices?

Microservices break a large application into several smaller services. Each service:

Runs independently
Has its own database
Communicates via API or message queue
Can be deployed & scaled separately
Handles a single business functionality

Example:
An eCommerce app might have the following microservices:

User Service
Product Service
Order Service
Payment Service
Notification Service

🎯 Why Use Node.js for Microservices?

✔ Non-blocking, event-driven
✔ Lightweight and fast
✔ Large ecosystem (npm packages)
✔ Easy to create REST APIs
✔ Perfect for containerization (Docker)
✔ Great for real-time communication

🏗 Node.js Microservice Architecture

A typical Node.js microservice setup includes:

Each service has:

🛠 Step-by-Step: Build a Simple Node.js Microservice

Here we will build:

User Service
API Gateway

📌 1. Create User Service

Install Express

server.js

const express = require("express");
const app = express();
app.use(express.json());

app.get("/users", (req, res) => {
res.json([
{ id: 1, name: "Vipul" },
{ id: 2, name: "Sanjit" }
]);
});

app.listen(4000, () => {
console.log("User Service running on port 4000");
});

const express = require("express");

const app = express();

app.use(express.json());

app.get("/users", (req, res) => {

res.json([

{ id: 1, name: "Vipul" },

{ id: 2, name: "Sanjit" }

]);

});

app.listen(4000, () => {

console.log("User Service running on port 4000");

});

Run service:

User service will run on:
👉 http://localhost:4000/users

🚪 2. API Gateway (using Express Gateway or custom)

Install:

server.js (API Gateway)

const express = require("express");
const { createProxyMiddleware } = require("http-proxy-middleware");

const app = express();

app.use("/users", createProxyMiddleware({
target: "http://localhost:4000",
changeOrigin: true
}));

app.listen(3000, () => {
console.log("API Gateway running on port 3000");
});

const express = require("express");

const { createProxyMiddleware } = require("http-proxy-middleware");

const app = express();

app.use("/users", createProxyMiddleware({

target: "http://localhost:4000",

changeOrigin: true

}));

app.listen(3000, () => {

console.log("API Gateway running on port 3000");

});

Now clients call only gateway:
👉 http://localhost:3000/users

API Gateway forwards to User Service.

🔄 Communication Between Microservices

1. Synchronous (REST API)

Fast, simple
But tightly coupled

2. Asynchronous (Message Queue)

Best options:

RabbitMQ
Kafka
Redis Pub/Sub
AWS SQS

🧰 Database per Microservice

Each microservice should have its own database:

Microservice	Database
User Service	MongoDB
Order Service	PostgreSQL
Product Service	MySQL

This avoids coupling and increases reliability.

🐳 Dockerizing Node.js Microservices

Example Dockerfile:

Build image:

📡 Using Kubernetes for Deployment

Each service gets:

Deployment
Service
ConfigMap
Secret

Example:

🛡 Security in Microservices

Use JWT Authentication

Generate token in Auth Service
API Gateway verifies token
Only authenticated requests go to microservices

Example JWT Middleware:

const jwt = require("jsonwebtoken");

module.exports = function (req, res, next) {
let token = req.headers["authorization"];
if (!token) return res.status(401).send("Access denied");

try {
const decoded = jwt.verify(token, "SECRETKEY");
req.user = decoded;
next();
} catch {
res.status(400).send("Invalid token");
}
};

const jwt = require("jsonwebtoken");

module.exports = function (req, res, next) {

let token = req.headers["authorization"];

if (!token) return res.status(401).send("Access denied");

try {

const decoded = jwt.verify(token, "SECRETKEY");

req.user = decoded;

next();

} catch {

res.status(400).send("Invalid token");

}

};

📏 Best Practices for Node.js Microservices

✔ Use API Gateway
✔ Separate databases
✔ Use Docker + Kubernetes
✔ Add logging (Winston / Morgan)
✔ Use environment variables (.env)
✔ Central error handling
✔ Use asynchronous messaging
✔ CI/CD pipelines

🎉 Conclusion

Node.js microservices make applications:

Scalable
Maintainable
Faster to develop
Easy to deploy

You can expand this architecture by adding:

Auth service
Payment service
Notification service
Logging service
Monitoring (Prometheus + Grafana)

Node.js Microservices

🚀 Node.js Microservices Tutorial

✅ What Are Microservices?

🎯 Why Use Node.js for Microservices?

🏗 Node.js Microservice Architecture

🛠 Step-by-Step: Build a Simple Node.js Microservice

📌 1. Create User Service

server.js

🚪 2. API Gateway (using Express Gateway or custom)

server.js (API Gateway)

🔄 Communication Between Microservices

1. Synchronous (REST API)

2. Asynchronous (Message Queue)

🧰 Database per Microservice

🐳 Dockerizing Node.js Microservices

📡 Using Kubernetes for Deployment

🛡 Security in Microservices

Use JWT Authentication

📏 Best Practices for Node.js Microservices

🎉 Conclusion

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Node.js Microservices

🚀 Node.js Microservices Tutorial

✅ What Are Microservices?

🎯 Why Use Node.js for Microservices?

🏗 Node.js Microservice Architecture

🛠 Step-by-Step: Build a Simple Node.js Microservice

📌 1. Create User Service

server.js

🚪 2. API Gateway (using Express Gateway or custom)

server.js (API Gateway)

🔄 Communication Between Microservices

1. Synchronous (REST API)

2. Asynchronous (Message Queue)

🧰 Database per Microservice

🐳 Dockerizing Node.js Microservices

📡 Using Kubernetes for Deployment

🛡 Security in Microservices

Use JWT Authentication

📏 Best Practices for Node.js Microservices

🎉 Conclusion

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