App Purchase for Product

I am developing an app and don't know much about App Purchase (IAP).

About app : It's an app for a pub. Users can buy subscriptions after they login.

Product : There will be different subscriptions. Let's say that user buys Package C, it means that they can drink up till 50$ from the bar for 25$ for that week between 16 - 22 o'clock.

Purchase : I can make this in 2 way. But don't know which one is the best :

1 -) After user clicks on purchase, I can open a webview and direct them to this Pub web page, then user enter their details and make a purchase at the site. When they refresh their account at the app, their credit will be updated for their account. I prefer this way but not sure if buying subscription is allowed outside of the app.

2 -) User clicks on purchase and everything with purchase happens at the app with App Purchase API. But don't know if it is allowed with Apple since the product is not something with the app itself (like unlocking a function at the app). Bartender has to do register each users drinks and update the balance at the app. I am asking this because I have read "You may not use the In-App Purchase API to offer goods or services to be used outside of Your Application"

I don't want to start to implement and finding out that it is wrong the way so it will be really helpful if you guide me the wring solution to implement...

Thanks


App Purchase for Product
 
 
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