Definition:
ATT (App Tracking Transparency) is Apple's opt-in privacy framework that requires all apps on the App Store to request explicit user permission before tracking their data across apps and websites for advertising and targeting purposes.
What is App Tracking Transparency?
Before iOS 14.5, advertisers could access a device's IDFA by default. Users had to actively seek out the Limit Ad Tracking setting to prevent it. ATT reversed that dynamic entirely.
Under ATT, apps must explicitly ask users for permission to track them across other apps and websites. The request comes in the form of a system-level popup that gives users a simple choice: allow tracking or ask the app not to track. If a user does not grant permission, the app receives a string of zeros in place of the IDFA, making individual-level tracking impossible.
It is one of the most significant shifts in mobile advertising in recent years, and its impact on how marketers measure and optimize campaigns has been substantial.
How Does App Tracking Transparency Work?
When a user opens an app that wants to access their IDFA, iOS presents a native ATT prompt. The prompt displays the app's name and a brief description of why it wants to track, followed by two options:
Allow
The app can access the user's IDFA and use it for tracking and attribution
Ask App Not to Track
The IDFA is replaced with zeros and the app cannot use it for tracking purposes
A few important things to know about how ATT works in practice:
- Apple only allows the native ATT prompt to be shown once per device per app
- The prompt is mandatory for any app that collects and shares user data with third parties for tracking purposes
- Users can change their ATT preferences at any time in iOS Settings under Privacy and Security, then Tracking
Apps that do not show the ATT prompt are not permitted to track users regardless
Does My App Need ATT?
If your app targets users on iOS 14.5 or above and collects data that is shared with third parties for advertising or tracking purposes, ATT is mandatory. This includes sharing data with MMPs like Tenjin, ad networks, and analytics platforms that use that data to track users across different apps.
If your app only uses data internally and does not share it with any third parties for tracking, the ATT prompt may not be required. When in doubt, Apple's guidelines are the definitive reference.
How to Enable and Manage ATT Permissions
For users who want to manage their ATT settings:
Go to Settings, then Privacy and Security, then Tracking. From here you can see which apps have requested tracking permission and toggle access on or off for each one individually. You can also toggle off "Allow Apps to Request to Track" entirely, which automatically denies all future ATT requests without showing the prompt.
For developers implementing ATT:
The ATT prompt is triggered using Apple's AppTrackingTransparency framework. The timing and placement of the prompt within the app flow is one of the most important decisions you will make, since you only get one chance to show it per device.
How to Improve Your ATT Opt-In Rate
Because Apple limits the native prompt to a single appearance per device, the moment and context in which you show it matters enormously. A few approaches that consistently improve opt-in rates:
Use a Pre-Prompt
Show a custom message before the native ATT popup appears. Use it to explain clearly and simply why tracking helps the user, whether that is a better ad experience, more relevant content, or supporting free access to the app. Keep it short and genuine.
Time It Well
Showing the ATT prompt at the very first app launch, before a user has had a chance to engage with your app, tends to perform worse than showing it after the user has experienced some value. Find a natural moment in the onboarding flow where the request feels less intrusive.
Be Transparent About The Benefit
Users are more likely to opt in when they understand what they are agreeing to and why it helps them. Vague or confusing messaging works against you.
Test Your Messaging
Different pre-prompt copy performs differently across audiences and app categories. A/B testing your pre-prompt is one of the more straightforward ways to improve opt-in rates without changing the underlying product experience.
The Impact of ATT on Mobile Marketing
ATT has had a direct and lasting impact on the mobile advertising industry. With a significant portion of iOS users opting out of tracking, the volume of granular, user-level IDFA data available to advertisers has dropped considerably. This has affected:
- Attribution accuracy: Without IDFA, deterministic matching is not possible for opted-out users
- Retargeting: Users who opt out cannot be reached through IDFA-based retargeting campaigns
- Lookalike audiences: Smaller pools of consented users mean less data to build audience models from
- Campaign optimization: Less individual-level data makes real-time bidding and creative optimization harder
The industry response has involved a combination of privacy-preserving measurement frameworks, probabilistic attribution methods, and aggregated data modeling.
SKAdNetwork: Apple's Attribution Answer to ATT
To give developers and advertisers a way to measure app install campaigns without relying on IDFA, Apple developed SKAdNetwork. It is a privacy-centric attribution framework that reports campaign performance at an aggregated level, with a time delay, and without exposing individual user data.
SKAdNetwork is not a perfect replacement for IDFA-based attribution, but it has become an essential part of the iOS measurement toolkit. Tenjin supports SKAdNetwork fully, helping you get the most out of the data it provides while navigating its limitations.
Is There an ATT Equivalent on Android?
Android has made its own moves in a similar direction. Starting with Android 12, Google gave users the ability to delete their advertising ID (GAID) entirely. Google has also deprecated third-party cookies and has signaled further restrictions on the data that can be shared via GAID over time.
While Android's approach is less prescriptive than Apple's ATT framework, the underlying direction is the same. Privacy is becoming a default rather than an option, and mobile marketers need measurement strategies that work in that environment.