I am working on an app that enables users to control a physical product that they buy. We are planning on launching a feature that lets users pay a monthly/yearly subscription fee in order to let them use our marketplace that hosts automations to the physical product that developers can use to make cool things for the physical product as well as earn some money.
I looked at the App Store Guidelines since I am not sure if this should be an IAP or if it should be handled through our own marketplace.
However after reading these guidelines I am inclined to believe that this feature should not be an IAP:
.3(e) Goods and Services Outside of the App: If your app enables people to purchase physical goods or services that will be consumed outside of the app, you must use purchase methods other than in-app purchase to collect those payments, such as Apple Pay or traditional credit card entry.
.4 Hardware-Specific Content: In limited circumstances, such as when features are dependent upon specific hardware to function, the app may unlock that functionality without using in-app purchase (e.g. an astronomy app that adds features when synced with a telescope). App features that work in combination with an approved physical product (such as a toy) on an optional basis may unlock functionality without using in-app purchase, provided that an in-app purchase option is available as well. You may not, however, require users to purchase unrelated products or engage in advertising or marketing activities to unlock app functionality.
Thanks!