WebSocket (https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API) is a communication protocol that works on top of TCP. It provides a full-duplex communication channel over a single TCP connection. It was standardized by W3C (https://www.w3.org). It is lightweight and enables real-time communication between a client and a server. In terms of web applications, this enables the server to communicate with the client app in the browser without a request from the client. This opens the door to push data from server to client in real time and for implementations such as real-time chat and notifications. On the server-side, JHipster relies on Spring, which provides the necessary support (https://spring.io/guides/gs/messaging-stomp-websocket/) to work with WebSocket.