Server-Sent Events (SSE) are a technology that allows a web server to push data to a client in real-time, without the need for the client to request it. It is a server push technology enabling a browser to receive automatic updates from a server via HTTP connection without resorting to polling. These are a one way communications channel - events flow from server to client only.

An example of how SSE works is when you are using a weather app on your mobile device. The app displays the current temperature and forecast for your location. As the day progresses, the app updates the information in real-time based on the latest data from the server. This is made possible by SSE, which allows the server to push the updated data to the client as soon as it becomes available.

In this scenario, the server is responsible for generating and sending the data to the client, while the client is responsible for displaying the data in real-time. The server sends the data to the client as a stream of events, with each event containing information about the current temperature and forecast. The client listens for these events and updates the app's user interface accordingly.

Overall, SSE provides a powerful way for web developers to create real-time applications that can update the user experience in near-real-time, without requiring the user to constantly refresh the page or request new data from the server.