WebSocket is a computer communications protocol that enables full-duplex interaction between a web browser (or other client application) and a web server with lower overhead than half-duplex alternatives such as HTTP polling, facilitating real-time data transfer from and to the server. It provides simultaneous two-way communication channels over a single Transmission Control Protocol (TCP) connection. WebSocket is a stateful protocol, which means the connection between client and server will keep alive until it is terminated by either party (client or server). WebSocket is bidirectional, a full-duplex protocol that is used in the same scenario of client-server communication, unlike HTTP it starts from ws:// or wss://. WebSocket is distinct from the Hypertext Transfer Protocol (HTTP) used to serve most webpages, but it is designed to work over HTTP ports 443 and 80 as well as to support HTTP proxies and intermediaries, thus making it compatible with HTTP.

The WebSocket protocol enables ongoing, full-duplex, bidirectional communication between a web client and a web server over an underlying TCP connection. The WebSocket connection is kept alive for as long as needed, allowing the server and the client to send data at will, with minimal overhead. WebSocket is used for real-time, event-driven communication between clients and servers, and it is particularly useful for building applications requiring instant updates, such as real-time chat, messaging, and multiplayer games. WebSocket enables two-way interactive communication sessions between client and server without having to poll the server for a reply, providing both speed improvements and real-capabilities over other protocols.

In summary, WebSocket is a protocol that enables full-duplex, bidirectional communication between a web client and a web server over a single TCP connection, allowing real-time data transfer from and to the server with lower overhead than half-duplex alternatives such as HTTP polling. It is used for real-time, event-driven communication between clients and servers, and it is particularly useful for building applications requiring instant updates, such as real-time chat, messaging, and multiplayer games.