WebSocket

WebSocket is a communication protocol, standardised in 2011, that opens a single long-lived connection between a client, such as a browser or trading program, and a server, over which both sides can send messages at any time. Ordinary web requests work like letters: the client asks, the server answers and the exchange ends. A WebSocket works more like an open phone line, so the server can push updates the moment they happen. This makes it the usual choice for chat, live dashboards and trading. Crypto exchanges offer WebSocket feeds alongside their standard APIs so that traders receive price ticks, trades and order book changes instantly, which trading bots rely on. Connections can drop, so programs must reconnect and resynchronise to avoid acting on stale market data.