Quite often there are situations, where one needs dynamically changing information proactively delivered, as fast as possible.
Stock market info is the poster child here, but there are quite a few other day-to-day use cases that also require close to real-time display of relevant data on many screens and across locations. Traffic information, factory line status, logistic tracking are to name as samples here.

Looking at the Microsoft technology stack, SignalR is the tool of choice to tackle these requirements.
SignalR leverages several different approaches such as WebSockets, Server Sent Events or Long Polling, transparently for developers in the background, to deliver information needed in the best way possible. All based on the connectivity scenario / quality of a client application.
It is great to see that SignalR is now provided in “Serverless Mode” by Azure SignalR Service, which takes away scaling and infrastructure maintenance effort for this service from developers.

Following the very efficient “low code/serverless” approach, I am always propagating, I want to recommend having a look at this interesting sample, showing how to-do real-time communication leveraging the Serverless SignalR Service in combination with Azure Functions.
Take it from me, SignalR is a great and fun technology to work with!
Alexander