body: I just read about Apple's [App Store Review Guideline](https://developer.apple.com/app-store/review/guidelines/#in-app-purchase):
  
  
  
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  > Apps may not include buttons, external links, or other calls to action that direct customers to purchasing mechanisms other than IAP.
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  What's the scope of this requirement? Does it only apply to payment to `unlock features or functionality within your app` or all payment behavior? Do online payment apps (Line Pay, Alipay) violate this guideline? After all, their sole purpose is to direct customers to their own payment mechanism.
  
  
  
title: Mobile payment app: infringement of Apple's IAP guideline?