I downloaded an app with my second apple ID from itunes and created an account using a phone number.

I noticed I can't use my Apple music since I'm considered signed in to the second apple ID, while I'm paying for music using my first apple ID.

If I sign into my first ID, can the app know that I am signed into that first apple ID?

I'm worried about privacy. don't want the app to connect me to the first appleID.

2 Answers 2


Third party apps do not know which Apple ID you have used to sign into various Apple services on the phone. They're not able to request information - not directly on the phone, and not from Apple's servers.


Apps can use CloudKit to request iCloud Apple ID information. This only returns information about the Apple ID used for iCloud, so not the Media & Purchases Apple ID.

A user identity provides identifiable data about an iCloud user, including their name, user record ID, and an email address or phone number. CloudKit retrieves this information from the user’s iCloud account. A user must give their consent to be discoverable before CloudKit can provide this data to your app.

CKUserIdentity, emphasis mine

Using requestApplicationPermission for userDiscoverability, access must be granted by accepting the following prompt:

Allow people using app name to look you up by email?

Apps granted access can perform a CKDiscoverUserIdentitiesOperation and retrieve a CKUserIdentity.

  • Perhaps we should clarify that this is part of the social features of CloudKit where you can share data in one app with other users. Basically you need to know the email address in order to do a lookup in the example here - so that can't be used to find out which Apple ID is logged in to Apple Music on the local phone.
    – jksoegaard
    Commented Jun 26, 2021 at 16:11

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