WebSockets (basics) interview questions

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1. What is WebSocket Protocol?

   WebSocket is a communication protocol that provides full-duplex (bidirectional) communication channels over a single TCP connection. Unlike HTTP, which follows a request-response model where the client requests and the...

2. How do you scale WebSocket applications?

   Scaling WebSocket applications to handle massive concurrent connections requires multiple strategies working together. The fundamental challenge is that WebSocket connections are stateful and long-lived, unlike...

3. What is the WebSocket Handshake?

   The WebSocket handshake is the process of upgrading an HTTP connection to a WebSocket connection. It starts with the client sending an HTTP GET request with specific headers indicating intent to upgrade to WebSocket....

4. How do WebSockets handle Message Framing?

   WebSocket message framing defines the structure of data sent between client and server after the handshake completes. Each WebSocket message is wrapped in a frame containing: FIN bit (indicates if this is the final...

5. How do you handle Real-Time Notifications with WebSocket?

   Real-time notifications require architecture to efficiently deliver messages from server to clients subscribed to notification events. Basic Approach: When an event occurs (user commented, post updated), the server...

6. What are the main differences between WebSocket and HTTP?

   WebSocket and HTTP are fundamentally different communication protocols with distinct characteristics. Communication Model: HTTP is request-response - client sends request, server responds, connection closes. WebSocket...

7. How do you handle Connection Reconnection in WebSocket?

   Reconnection handling is critical for robust WebSocket applications because network connections can fail unexpectedly. Automatic Reconnection: Implement client-side logic to detect disconnection and automatically...

8. What are WebSocket Subprotocols?

   WebSocket subprotocols define specific protocols for communication after WebSocket connection is established. WebSocket itself is just a transport layer - it provides bidirectional communication but doesn't specify what...