Glossary/Privacy & Identity/App Tracking Transparency (ATT)
Privacy & Identity
App Tracking Transparency (ATT)
Apple's rule requiring apps to get permission before tracking users across apps and sites.
By Brandon Mina·CEO, BrandPilot AI·Updated November 2026
Short answer
App Tracking Transparency (ATT) is Apple's framework, introduced with iOS 14.5 in 2021, that requires apps to ask users for permission before tracking them across other companies' apps and websites. Without consent, apps cannot access the device's advertising identifier (IDFA). Low opt-in rates sharply reduced mobile targeting and attribution, accelerating industry-wide signal loss.