SignalR allows you to integrate with ASP.NET Core in real time.

Clients can connect to SignalR through the use of a front-end web technology, such as React, or Blazor Wasm.

From there, they can send and receive messages from the ASP.NET Core application in real time.

SignalR can be used on real-time applications, such as a chat messaging service, or an online game.

SignalR has been around for a long time and has adapted as technology has developed.

In recent times, SignalR uses WebSocket's which is supported on all modern browsers to send and receive messages in real-time. If WebSocket does not exist on the user's browser, it has other ways of establishing a connection, such as long polling.