WebSocket Explained: How Full-Duplex Protocol Enables Real-Time Web Communication

WebSocket is a communication protocol that allows clients and servers to exchange data simultaneously over a single, persistent TCP-based connection, unlike traditional HTTP which requires the client to initiate every exchange. The protocol supports full-duplex communication, meaning both sides can send and receive data at the same time without waiting for the other, similar to a phone call rather than a walkie-talkie. WebSocket was developed as a solution to the inefficiencies of HTTP-based workarounds such as polling and long polling, which were commonly used to simulate real-time communication. While its design draws from raw TCP, WebSocket adds a minimal layer of web-aware abstractions to ensure compatibility with browser security models and message framing. The protocol operates in three phases: an HTTP-based opening handshake that upgrades the connection, a data transfer phase, and a closing sequence.