Sarah Perez, writing for TechCrunch, has published a detailed set of answers about Apple’s upcoming ‘Sign In with Apple’ feature on iOS, macOS, tvOS, watchOS and to an extent, Android and the web.

The ‘Sign In with Apple’ feature is one of the most exciting announcements to come out of WWDC ’19 for me, and I’m really looking forward to its release. However, I do have a few concerns, all of which still remain unanswered.

  • What happens to your account when you sign out of iCloud and Sign In with another Apple ID?
  • What happens when you want to use a developer’s app on multiple devices that don’t use the same Apple ID?
  • Will Apple allow you to choose/specify a custom email address that is separate from the Apple ID to receive marketing emails from the developers?

I believe that SIWA is a phenomenal new feature and I see a majority of developers adopt this feature for their apps. I just hope that SIWA doesn’t end up being the only Sign In option in apps going forward.