We are developing an application which allows user to synchronize fitness band data, such as step count and sleep tracker with mobile device. we give the hardware (fitness band) free to users with premium subscriptions.
We also have several other premium features such as expert consultation, goals tracker etc. all this feature are available with premium subscription. We also have plans to sell few fitness products in the future.
My question is, whether apple allows us to integrate third party payment vendor or It is mandatory to stick with In-app purchase. I went through App Store Review Guidelines. and It does not seem clear enough on the policy with respect to our model.