Identifier for Vendors (IDFV) | Definition
IDFV stands for “identifier for vendors” and is a universally unique identifier (UUID) used by Apple on many of its devices, including iPhone, iPad, etc. The IDFV is 32 characters long with 4 dashes and can be used to distinguish individual devices engaging with an app.
Unlike the identifier for advertisers (IDFA) which is unique to each app on a device, the IDFV is unique to the app developer account, and is identical across all apps published by that developer that are on the user’s device. This enables the IDFV to be used for attribution on cross-promotional acquisition efforts within a developer’s own portfolio of apps. Availability of the IDFV will not be affected by the AppTrackingTransparency (ATT) framework, which requires user opt-in to access the IDFA.