Does Apple's new tracking policy block deep linking?
Based on Apple's language on their User Privacy and Data Use page, our understanding of the ATT policy is that it is specific to tracking, attribution, and targeting for paid ads and data brokers. This means that core app UX functionality (like deep linking) is not within the scope of the App Tracking Transparency policy, except in situations where an app attempts to abuse this functionality to work around other limitations of the ATT policy.
On April 19, 2021, Apple further reinforced this distinction around ad-related use cases via a new FAQ item on the User Privacy and Data Use page:
The wording of the question references 'deep linking' and 'deferred deep linking', and the answer makes it clear that the behavior Apple considers objectionable is using such functionality to '…pass unique identifiers or create a shared identity of the user between applications from different companies for ad targeting, ad measurement or sharing with a data broker'.
In other words, ATT prohibits utilizing deep linking technology for the purposes of working around the policy's restrictions on tracking paid ads and sharing data with data brokers. This is perfectly in line with the policy's other prohibitions (for example, on fingerprinting), and reflects Apple's goals of a) limiting the IDFA on iOS, and b) placing policy limitations on any method that could be used to bypass these IDFA limits.
Branch agrees with Apple's stance on this, and we're glad to see them make this move to keep deep linking focused on its original purpose: creating great product experiences for users.
In summary, Branch's understanding is that deep linking (including deferred deep linking) properly implemented for its intended purpose of user experience enhancement is still permitted on iOS 14.5+, whether the user opts in via ATT or not. We believe this is the case both when you build your deep linking implementation in-house, and when you legally establish a processor relationship with a vendor such as Branch.
Updated about 1 year ago