Real-time communication enables your Web API to push updates or notifications to connected clients in real-time. In ASP.NET Core, you can implement real-time communication using the SignalR library. SignalR provides a high-level API that abstracts the complexities of real-time communication protocols like WebSockets or Server-Sent Events. You can define SignalR hubs to handle client-server communication and broadcast messages to connected clients. By integrating SignalR into your Web API, you can build features such as chat applications, real-time dashboards, or collaborative tools that require instant updates and synchronization between clients and the server.