Using email in iOS apps?

Question

iOS

Interested in the question regarding the possibility of using e-mail in the iOS application for user authorization. I've seen on stackoverflow that this won't let apple through, as it prevents the user's e-mail and birthday from being used to identify them. However, the App Store is full of applications that authorize via e-mail. Can anyone clarify this situation?
Thank you.

Answer 1

There are no problems in using e-mail for registration. But an application that requires unconditional registration for no good reason can be turned down for review. If there is such an opportunity, then the application should work without registration, and registration should be required only for functionality tied to the user.
There must also be a good reason for requiring personal information about the user (birthday).

We found that your app requires customers to register with personal information to access non-account-based features, which is not in compliance with the App Store Review Guidelines.
Apps cannot require user registration prior to allowing access to app features and content that are not associated specifically to the user. User registration that requires the sharing of personal information must be optional or tied to account-specific functionality. Additionally, the requested information must be relevant to the features.