WebSocket

WebSocket is a networking protocol that enables real-time, bidirectional communication between a client, such as a web browser or trading bot, and a server over one long-lived connection. Unlike traditional HTTP requests, which are typically request-response and short-lived, a WebSocket connection stays open so both sides can send data at any time.

A WebSocket session usually starts with an HTTP-based “handshake.” The client requests an upgrade from HTTP to WebSocket, and once the server accepts, the connection becomes a persistent, full-duplex channel. From that point on, the client and server exchange messages without repeatedly opening new connections. This reduces overhead and latency, which is essential when systems need to react quickly to new information.

In crypto, WebSockets are commonly used for streaming live market and network data. Exchanges and data providers often offer WebSocket APIs that publish continuous updates such as trades, order book changes, ticker updates, and funding rates. For example, a trading interface can use a WebSocket feed to update a price chart instantly, or a market-making bot can subscribe to order book channels to adjust quotes as liquidity changes.

WebSockets are also useful in blockchain-facing apps. Wallets and explorers can subscribe to events like new blocks, mempool activity, or transaction confirmations so users see status updates immediately without refreshing a page. Some node and infrastructure services expose WebSocket endpoints for event subscriptions, allowing applications to respond to on-chain events in near real time.