Web Sockets Study Notes

Authenticating WebSocket Connections

Learn how to securely authenticate long-lived WebSocket connections, including handshake-time token validation, per-message authorization, and common security…

Backpressure in WebSockets

How to detect and handle slow consumers on a WebSocket connection before unbounded buffering leads to memory exhaustion or unresponsive clients.

Building a Real-Time Chat App

A hands-on walkthrough of designing a WebSocket-based chat application, from connection lifecycle and message schema to rooms, presence, and delivery guarantee…

Building a WebSocket Server with Node.js

Learn how to stand up a production-ready WebSocket server in Node.js using the `ws` library, from the handshake through broadcasting and horizontal scaling.

Close Codes and Error Handling

What WebSocket close codes mean, how to choose the right one, and how to build robust reconnect and error-handling logic around them.

Cross-Site WebSocket Hijacking

How attackers exploit the lack of same-origin enforcement on WebSocket handshakes, and the defenses that stop them.

Debugging WebSocket Connections

Practical techniques for diagnosing failed handshakes, dropped connections, and mysterious silent disconnects in WebSocket-based applications.

Opening and Closing Connections

How a WebSocket connection is established through the HTTP upgrade handshake and gracefully terminated using the closing handshake.

Ping/Pong and Heartbeats

How WebSocket ping and pong control frames keep connections alive and let both sides detect dead peers.

Rate Limiting WebSocket Connections

Strategies for throttling connection attempts and message throughput to protect WebSocket servers from abuse and resource exhaustion.

Reconnection Strategies

How to design client-side reconnect logic, backoff, and state resync so WebSocket-based apps recover gracefully from dropped connections.

Scaling WebSockets Horizontally

How to run WebSocket servers across many instances when every connection is a long-lived, stateful process pinned to one machine.

Socket.IO Explained

Understand what Socket.IO adds on top of raw WebSockets — rooms, namespaces, automatic reconnection, and transport fallback — and when it's the wrong tool for…

Subprotocols Explained

How the Sec-WebSocket-Protocol header lets client and server agree on an application-level messaging convention over a raw WebSocket connection.

Text and Binary Frames

How WebSocket messages are broken into frames, and the difference between UTF-8 text frames and raw binary frames.

The WebSocket Handshake

A step-by-step look at how a WebSocket connection is established, from the initial HTTP Upgrade request to the server's 101 Switching Protocols response.

Validating WebSocket Messages

Techniques for safely parsing, validating, and routing untrusted WebSocket message payloads to prevent crashes and injection attacks.

WebSocket Frames Explained

A look under the hood at how WebSocket messages are broken into binary frames, including opcodes, masking, fragmentation, and control frames.

WebSocket Security Basics

Foundational security considerations for WebSocket connections, from handshake origin checks to authentication and secure transport.

WebSockets Behind a Load Balancer

How to correctly configure load balancers, proxies, and timeouts so WebSocket handshakes and long-lived connections survive in production.

WebSockets in the Browser

A practical guide to the native browser WebSocket API — connecting, sending and receiving messages, handling reconnection, and working with binary data efficie…

WebSockets Interview Questions

Common WebSockets interview questions with clear, technically grounded answers covering the protocol, scaling, security, and comparisons to alternatives.

WebSockets Quick Reference

A condensed reference covering the WebSocket API, handshake headers, close codes, and common patterns for fast lookup while building or reviewing real-time fea…

WebSockets vs HTTP Polling

A comparison of WebSockets against short and long HTTP polling techniques for achieving near-real-time updates in web applications.