I'm seeking thoughts or examples from existing iOS mobile applications where users invite contacts to download the app. A unique identifier is required to establish a relationship between the inviter and the invitee to support the intended functionality. One thought was use a short code in the invitation but that requires the invitee to write down or remember that code because I believe the Apple App Store strips that invite code when the user is arriving through a deep link in the invite.
The other option I'm considering is having the inviter enter their contact's email address and have the invite sent through email with a link to the App Store, which works well but we run the risk of the invitee sign up using a different email address meaning that relationship between inviter and invitee wouldn't be established.
Any thoughts?