ATT (App Tracking Transparency)

How it works

The app asks the system to show a permission prompt. The user allows tracking or declines, and the system records the answer for that app. From then on the app can check its authorization status before it does anything that counts as tracking.

Apple's framework documentation says an app needs ATT if it collects data about people and shares it with other companies to track them across apps and websites.^[1] What Apple counts as tracking, and what happens to the IDFA when a user declines, is set out in the guide: App Tracking Transparency: what the prompt controls.

When it matters

It matters at two moments: when you add an SDK that shares user or device data with another company for advertising, and when you decide whether to show the prompt at all.

It does not switch off measurement. Apple's SKAdNetwork can be called regardless of tracking authorization status.^[2]

How it relates to attribution

ATT gives your iOS reporting two layers. Users who allow tracking can be attributed at device level. Apple's frameworks report installs from ads served through them at campaign level, whether or not the user allowed tracking.^[2] A self-attributing network and your attribution tool both work inside those two layers, and a provider's iOS report should show which layer each number comes from.