Where are things like: SignalR Core, Socket.IO, WebSocket, SignalR and Rest Api used?

Question

Unity

Hello,
please tell me where and how these technologies are used during the development of projects on unity3d?
SignalR Core, Socket.IO, WebSocket, SignalR and Rest Api
What do they do and why use them?
I met this feature on Youtube for some Hearthstone streamers during broadcasts: in the arena, they allowed viewers to build their own deck by voting in the chat for one or another proposed card. So, can any of the questions listed in the title of the question help in creating such a thing?

Answer 1

Yes

Answer 2

These technologies allow you to transfer data from viewers to the server.
These words may help, but I would suggest you familiarize yourself with HTTP POST, GET, and AJAX. These things will allow you to create interactive with viewers in a couple of lines of code.