I have a Flutter based application that runs on Windows, Linux, Web, iOS and Android. I'm getting ready to integrate the app store subscriptions and reviewed each of the various platform stores available. The Google Play Store and Apple App Store integrations for subscriptions is pretty straight forward. I can make REST calls to their Stores from my backend to determine subscription status and receive status changes to their subscriptions.
While exploring the Windows side of things, I'm not sure I fully understand it. Reading their documentation for getting the users subscriptions, it sounds like the API can only be used for UWP based apps. As this is a Flutter app, will I not be able to provision the needed add-ons within my Microsoft developer account for subscription services in the Windows Store? The following quote from the docs would suggest this to be the case.
This method can only be used by developer accounts that have been provisioned by Microsoft to be able to create subscription add-ons for Universal Windows Platform (UWP) apps. Subscription add-ons are currently not available to most developer accounts.
I'm not 100% sure on the subscription status since it's REST based when looking at the docs - it seems like I could make that call and MSFT wouldn't know I have a UWP app or not. However, the endpoint requires a MSFT Store ID which is created via their Microsoft Store Collections API. This API provides an endpoint for my servers to hit which is great. Unfortunately, the endpoint requires a Microsoft Store ID and it seems like the only way for the app to actually get the ID is using their UWP SDK. I can't find a REST based endpoint for that.
When it comes to Windows, am I out of luck? If so, then I guess the path forward would be to let users subscribe via Google or Apple stores, then have my backend services provide subscription status via JWT based on the mobile stores. Is that how most other people do cross-platform apps in other languages that have subscriptions?
