How can I implement a paid synchronization function for an android application through my server?

Question

Android

For a mobile application, you need to add the ability to synchronize data with other android devices. But it should be a paid feature. Most likely by subscription.
Synchronization will occur through its own server. At the same time, the user will need to have his own account on this server (and not be tied to the Google account that is on his device).
The sequence of user actions is as follows:

1. It registers on the server directly from the application
   
2. In the same place, in the application, pays for a subscription
   
3. It has the ability to synchronize (well, and other paid features)
   

The question is how to organize this architecture? Namely:

1. Is it possible to check the fact of payment on the server side? How?
   
2. Как предоставлять платный функционал для всех устройств, подключенных к аккаунту на нашем сервере (независимо, с какого устройства эта услуга была оплачена)?
   
3. Какие инструменты порекомендуете для работы с гугловским биллингом?
   

Answer 1

> Is it possible to check the fact of payment on the server side? How?
It is necessary to check on the server
https://habrahabr.ru/post/160911/
> How to provide paid functionality for all devices
to provide by account, from the server the application should receive a state
to open the functionality or not
> What tools do you recommend for working with Google billing?
purchases are visible in the Google console,
and providing access to the functionality lies on your base

Answer 2

Ничего сложного не вижу. Сделать подписку и все.