Realtime environment (Basics)

We want a computer interface (no matter if it is web-based or device software) on which 2 or more (but probably not more than 4 for the time being) can “play” simultaneously the same “game”. The term “game” is written in quotes, because the game is very simple and we can also provide the code for it. The software keeps track of their actions also registering the time they do something.