Mobile Tutorial Series – What is an IDFA or Apple Identifier for Advertisers?

By John Koetsier January 1, 2017

IDFA is the abbreviation for identifier for advertisers on iPhones. An IDFA is somewhat analogous to an advertising cookie, in that it enables an advertiser to understand that a user of a phone has taken an action like a click or an app install. That is called ad tracking. IDFAs take the place of cookies in mobile advertising delivered to iOS devices because cookies are problematic in the mobile world.

Advertisers are naturally interested in understanding the anonymized individuals that take advertising actions. IDFAs (and their Android siblings, Android Advertising IDs) help an advertiser identify the specific phone where the ad action takes place.

Semi-Permanent Device Identifiers

Third-party cookies, which are commonly used on the PC web for tracking, tend to have short life spans – anything from one to thirty days on average. By contrast, the IDFA doesn’t change unless a user decides to change it in their phone settings. Few consumers feel a need to take this action, so IDFAs can offer a better foundation for a persistent and anonymized consumer profile.


Before IDFA, advertisers could track actions on iPhones using a permanent device identifier called UDID, or universal device ID. The big advantage that IDFA offers over UDID is consumer choice. A UDID was a permanent device number, and sharing it could not be turned off, whereas users have the option to limit ad tracking, or to change their IDFA periodically.

IDFA is the only ID that Apple allows advertisers to use to understand the advertising actions on its phones. This reflects their commitment to the ideas of privacy and choice, while also enabling a robust advertising industry in which brands target likely responders and drive revenue for app and mobile publishers. Users that choose to can limit ad tracking by preventing the IDFA being passed to advertisers.

Using IDFA for Ad Tracking

When consumers take actions because of ads, like clicking a banner, playing a video, or installing an app, media companies can pass the IDFA with information about the consumer action that took place because of the advertising. Most media companies do pass IDFAs. Some media companies, including some large social networks, do not pass device IDs to advertisers, but do allow you to target specific IDs within their properties. Many companies also leverage IDFAs as a tool for fraud detection. By monitoring the stream of ad actions and associated IDFAs, advertisers get important signals that may indicate advertising fraud.


You may also occasionally hear about an ID called IDFV. This stands for identifier for vendors. An IDFV is assigned and shared by all apps from the same company. Sometimes companies with multiple apps base their marketing efforts and analyses on IDFV, because they only change if a user uninstalls all apps from a particular vendor.

Using IDFA for Mobile App Attribution

Using IDFAs and app attribution capabilities like those offered as part of the Singular platform, marketers can understand which campaigns, executions, and media partners were responsible for desirable consumer actions. Using these insights, they can calculate the ROI for every program and tactic and optimize their marketing to the most profit-generating tools. The IDFA also enables a marketer to target specific individuals that have taken actions in the past. For example:

  • Target people who have installed and deliver advertising that makes them relaunch the app
  • Create an audience of lapsed users and advertise to them to get them to come back to the app
  • Identify the people who have abandoned items in shopping carts, and advertise to them to get them to come back and complete their purchases

This sort of individual targeting is becoming increasingly common as programmatic media and social media advertising grow in popularity.

Looking for an attribution provider but not sure how to choose? Check out our 7 Things Your Mobile Attribution Tool Doesn’t Do (But Should) report to learn the key features and tools you need in a provider.

Download The Singular ROI Index to see the world’s first ranking of ad networks by app ROI.


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