Communication with for example waves tokens

[BlackTurtle]

Hello everyone.
I was wondering something,
is it possible to let only a certain of contract tokens interect with an API and how would this work?

For example I have a coin on waves, or neo or eth, and I want to create a website what offers premium only for this coin, is this possible with an api?

I was trying to understand how all those start-ups communicate with the tokens they issue, or aren't those linked?

I hope my question was clear and people can clearify this to me.

I also hope I posted in the correct section.