IDFA (Identifier for Advertisers)

The Identifier for Advertisers (IDFA) is a unique identifier linked to a mobile Apple terminal. It’s a way of uniquely identifying the terminal user to follow digital activity and suggest personalized content.

IDFA was once used, for example, to retarget a user based on actions taken within an app. Since the iOS 14 update in late 2020, this is no longer possible.

An example IDFA is: EA7583CD-A667-48BC-B806-42ECB2B48606. It’s the equivalent of Android’s AAID.