Cross platform subscription for app
I have an app running on iOS, Mac and (soon) android. Windows will follow.
The app is free to use, and data is stored locally. If the user wants to sync their data across their devices (say - their iPhone and Windows PC), then I want them to subscribe (with the subscription level based on the amount of cloud storage required).
First off - I want to support users who are not Apple (e.g. they have windows + android phone), so IAP alone is out. I also want to support users who are fully Apple (Mac+iPhone), so paying via the Google Store is out. I understand your services will support that, which is perfect for me.
But what I'm not clear on is how Apple and Google will look upon my app, where I provide expanded services based on a subscription that is not paid for via their stores. Wont that be breaking their ToS? Thanks for any guidance you can provide