Apple Soon to Require Justification for the Use of User Defaults API in iOS App Groups

Apple is now requiring developers to justify their use of certain APIs in iOS app groups. This measure aims to crack down on fingerprinting, a technique used to track users across different apps and websites. One of the APIs that requires justification is the User Defaults API, which is commonly used by iOS developers to store information such as user preferences. This requirement poses a challenge for developers who utilize app groups, a feature supported by Apple that allows multiple apps from the same developer to share a pool of User Defaults data. The one valid reason provided by Apple for using User Defaults does not cover cases where app groups are used. Developers are required to manually report their API usage and provide a reason code for each. They must also fill out a form to request approval for using an API if their use case is not covered by an existing reason. This new requirement has led to frustration among developers who argue that it is unnecessary for an API as commonly used as User Defaults. Many apps rely on shared User Defaults for seamless functionality between different apps. Despite the inconvenience, developers must comply with the new policy and justify their use of the User Defaults API.