🔹 What is WebSocket?

• WebSocket is a communication protocol.

• It provides full-duplex (two-way) communication between client (browser/app) and server.

• Unlike HTTP (request/response), WebSocket allows continuous data exchange once the connection is established.

🎯 Why WebSockets?

✅ Real-time communication
✅ Lower latency than HTTP
✅ Less overhead (no repeated HTTP handshakes)
✅ Useful for live applications

⚡ How It Works (Flow)

1️⃣ Handshake (Upgrade from HTTP)

• Client → sends an HTTP request with Upgrade: websocket header.

• Server → responds with Switching Protocols (101).

• Now, the connection is upgraded to WebSocket.

2️⃣ Persistent Connection

• Both client & server keep the channel open.

• Either side can send messages at any time.

3️⃣ Data Frames

• Data is sent in small frames (text or binary).

• Lightweight → reduces bandwidth.

🖼️ Analogy

• HTTP: 📩 Postman → knocks → delivers → leaves → comes again for next message.

• WebSocket: 📞 Phone Call → once connected, you talk freely until you hang up.

🛠️ Use Cases

🌍 Chat Apps – WhatsApp, Messenger
📈 Stock Market Tickers – Live stock updates
🎮 Gaming – Multiplayer real-time sync
🚖 Ride-Hailing Apps – Live driver tracking
🔔 Notifications – Instant alerts

⚖️ WebSocket vs HTTP

🎨 Visual Flow 

Client (Browser) 🖥️
⬇️ (Handshake over HTTP)
Server 🌐
⬆️ (Upgrade response)
🔗 Connection established!

➡️ Client sends messages (Chat, Game Move, Order)
⬅️ Server sends updates (Reply, Stock Prices, Notifications)