Realtime updates from SQL Server to front end

We have a SQL Server database which is called using our API.

The API is written in C#. The API feeds the front end. which is written in .net / MVC + AngularJS,

At the moment, data is loaded in the onload event handler of the page, or via interaction from the user (clicking a button).

What is the recommended way to have real time updates pushed to the front end? ie. if the database is updated via another means / another user, this is replicated instantly (or as close too) in the front end (as firebase works)

Source: AngularJS