express master guide

Express.js Learning Prerequisites

Before diving into Express.js, you should have a basic understanding of:

✅ JavaScript (ES6+ features)

✅ Node.js and npm (Node Package Manager)

✅ Asynchronous programming (Promises, async/await)

Install Express Js

npm init -y

Entry File Index.js

npm install express

create app.js

Express app

const express = require('express')
const app = express()
const port = 3000

app.get('/', (req, res) => {
  res.send('Hello World!')
})

app.listen(port, () => {
  console.log(`Example app listening on port ${port}`)
})

RUN The App

node app

Express is used in many real-world applications:

✔ REST API development

✔ E-commerce backend

✔ Authentication system (JWT, OAuth)

✔ Real-time apps with Socket.io

✔ Logging & monitoring systems

✔ File upload service

✔ Microservices architecture