We are an realestate company and are currently building a solution for our clients ( which includes mainly a website version and also App ) where the users can get access to some of the data we produce/fetch from various sources to give insights to our clients and help them make better real estate decisions. While some of the data they can access for free, we want to charge a fee (monthly/yearly) to get access to more sophisticated/premium data. They can access this information by logging in into our website using their provided credentials, we want to also create an App ( IOS/Android) where they can see the same info. There could be users who may only use the Website and never download the App or may use the App more often. And what happens if they stop using the App or switch to an Android device in future or vice versa. My question is do we have to go through the Apple App Subscription model and pay the 30% share to Apple/Google or we are allowed to collect the payments from users on the website using one of the external payment gateways. Idea is to get some guidance if there are obvious answers to what may be allowed/rejected to allow us to then spend efforts/time/money developing the solution in the right direction and not find out at the end that we have come down a wrong path.