WebSockets is an advanced communication protocol that provides a full-duplex, persistent communication channel over a single TCP connection between a client (like a web browser) and a server. Unlike the traditional request-response model of HTTP, once a WebSocket connection is established, it stays open, allowing both the client and server to send data to each other at any time without needing to initiate a new request. This bidirectional, real-time data flow is crucial for developing highly interactive and responsive web applications, such as live chat systems, online multiplayer games, and real-time financial data feeds.