IDFA (Identifier for Advertising)
IDFA (Identifier for Advertising)
IDFA is a unique, anonymous identifier assigned to each iOS device for the purpose of tracking and targeting advertising.

What is IDFA?

IDFA (Identifier for Advertising) is an identifier assigned to iOS devices for tracking and targeting ads. Mobile marketers use IDFA to track user engagement with their ads, measure the effectiveness of their campaigns, and target specific audiences. IDFA is unique to each device and cannot be used to identify an individual personally.

How does IDFA work?

IDFA is just like a cookie on the web. When an app requests access to the user's IDFA, the user's device generates a unique IDFA specific to that device. This IDFA is then used to track the user's engagement with advertisements within the app, including the types of ads they have viewed, the number of times they have interacted with an ad, and the actions they have taken as a result of viewing an ad.

This data is collected anonymously and is used by marketers to measure the effectiveness of their campaigns and target specific audiences. Marketers may use various methods of targeting, such as demographic targeting (e.g. targeting ads to people in a particular age group or income level) or behavioral targeting (e.g. targeting ads to people who have shown an interest in a specific product or service).

Why is IDFA important?

Mobile Attribution

IDFA allows marketers to track user engagement with their advertisements and measure the effectiveness of their campaigns. This includes information on the types of ads that have been viewed, the number of times an ad has been interacted with, and the actions taken as a result of viewing an ad. This data is critical for mobile marketers to understand where their users are coming from and how their campaigns perform.


IDFA is also important for targeting specific audiences. IDFA allows marketers to target audiences based on their engagement with advertisements, which can help increase their campaigns' relevance and effectiveness.


IDFA is an essential tool for personalizing the advertising experience for users. By tracking user engagement and targeting specific audiences, marketers can deliver more personalized ads to users, which can help to improve the overall user experience.

Impact on IDFA following iOS 14.5 update

With the release of iOS 14.5, Apple introduced App Tracking Transparency (ATT), which affected how IDFA is used in mobile marketing. App Tracking Transparency is a feature that requires app developers to ask for users' permission before tracking their data for advertising purposes. If the user denies tracking, the app will not be able to access their IDFA and will not be able to track their data.

The introduction of App Tracking Transparency greatly impacted mobile marketers' ability to track user engagement and target specific audiences. With users having the ability to opt out of tracking, there is a risk that the data available for targeting and measurement may be reduced, potentially impacting the effectiveness of marketing campaigns.

As an alternative method for measuring the effectiveness of advertising campaigns, Apple introduced SKAdNetwork (SKAN). SKAdNetwork helps to preserve user privacy by avoiding the collection of user-level data and uses a randomized assignment process to attribute conversions to campaigns. However, SKAdNetwork is not intended to replace IDFA, but rather to provide an alternative option for ad measurement that respects user privacy.

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