💬 Node.js Real-Time Chat Application

A real-time chat application built with Node.js, Express, and Socket.IO that enables multiple users to exchange messages instantly in a shared chat room over WebSockets.

💡 After building this, I developed Open Chat Application — a completely separate, far more complex project with chat rooms, user authentication, and live deployment on Render.

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✨ Features

• ⚡ Real-time bidirectional messaging via WebSockets
• 👥 Multi-user support in a shared global chat room
• 🔔 Join & leave notifications broadcast to all users
• 🌑 Clean dark-themed responsive UI
• 🔄 Auto-scroll to latest messages

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🛠️ Tech Stack

Layer	Technology
Runtime	Node.js
Framework	Express.js
Sockets	Socket.IO
Frontend	HTML, CSS, JavaScript

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📁 Project Structure

ChatApp/
├── public/
│   ├── main.html       # Chat UI
│   ├── app.js          # Client-side Socket.IO logic
│   └── cell.css        # Dark theme styling
├── server.js           # Express + Socket.IO server
└── package.json

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⚙️ Getting Started

1. Clone the repo

git clone https://github.com/Harshith1702/Nodejs-real-time-chat
cd Nodejs-real-time-chat

2. Install dependencies

npm install

3. Start the server

node server.js

4. Open in browser

http://localhost:4000

💡 Open multiple browser tabs to simulate multiple users chatting in real time.

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🔌 How It Works

Client A  ──────────────────────────────────────────►  Server (Socket.IO)
  │   emit('chat-message', msg)                              │
  │                                                          │ io.emit('message', ...)
  │                                                          ▼
Client B  ◄─────────────────────────  Receives message instantly
Client C  ◄─────────────────────────  Receives message instantly

• On connect → user enters their name via prompt
• Server stores socket.username and broadcasts join event
• Messages are emitted to all connected clients via io.emit()
• On disconnect → server notifies remaining users

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📸 Screenshots

Interface	Chat in Action

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💡 What I Learned

• Real-time bidirectional communication using Socket.IO
• Difference between socket.emit(), socket.broadcast.emit(), and io.emit()
• Managing multiple concurrent WebSocket connections
• Serving a frontend with Express static middleware

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🔗 Related Projects

• Open Chat Application — A separate, more advanced project featuring chat rooms, authentication, and live deployment on Render

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Built as a Node.js lab mini project — 3rd Semester | CMR Technical Campus