Sending requests between end to end devices in ionic

hey guys how can i send a request to a user when a button is pressed?

for example user 1 sends a request, the request is sent to user2, and user2 accepts or rejects the requests

and user 1 is notified by about the decision of user 2

how can this be done in ionic 2/3?

thanks

You need something like firebase

hi i am using firebase authentication and firestore database