SaaS subscription across iOS, Android and Web We have three different forms of distribution for our SaaS (Web, Android and iOS) all currently reviewed and in-store in their free form ($0).

Our business model is focussed around a single subscription across all platforms and was hoping to use our existing system of Stripe > Webhook to updates all services of a users status.

Heads down in the development has overlooked the very confusing, constantly changing and expensive (70/30 split!) guidelines that Apple publishes.

We've developed blindly as looking at apps like Dropbox and many others offer the same subscription / account across all platforms.

My questions is how are they doing it? IAP? External subscription? From the guidelines you are not allowed to link to a 'Buy / Subscribe' button.
You're not allowed to link to an external payment method, but saying that the app requires payment outside of the app is fine.

For example, mentioning in the app description that the app “requires a valid subscription to x” is acceptable, whereas having a link inside the app to “purchase your subscription here” is not unless that purchase is through IAP.