What is WebSocket API?

WebSocket is a computer communications protocol that opens an interactive communication session between the user's browser and a server. Unlike HTTP, WebSocket provides full-duplex communication.

Why WebSocket?

In the traditional HTTP model, the client sends a request and the server responds. It is difficult for the server to spontaneously send data (push) to the client. WebSocket solves this problem.

How it Works?

1. Handshake: The client sends a standard HTTP request to the server saying "Let's switch to WebSocket" (Upgrade header).
2. Connection: If the server accepts, the TCP connection remains open.
3. Data Flow: Now both parties can send data to each other at any time. Data flows with very low latency, without the overhead of HTTP headers.

Use Cases

• Chat Applications: Instant messaging like WhatsApp, Slack.
• Live Feeds: Sports scores, stock market data.
• Online Gaming: Synchronizing player movements in multiplayer games.
• Collaborative Tools: Apps like Google Docs where simultaneous editing occurs.

WebSocket is one of the most critical technologies enabling the modern web to be "live" and "instant".