{"id":8241,"date":"2026-10-28T08:17:00","date_gmt":"2026-10-28T01:17:00","guid":{"rendered":"https:\/\/adtek.agency\/skadnetwork-adattributionkit-ios-app-ads\/"},"modified":"2026-10-28T09:44:34","modified_gmt":"2026-10-28T02:44:34","slug":"skadnetwork-adattributionkit-ios-app-ads","status":"publish","type":"post","link":"https:\/\/adtek.agency\/en\/skadnetwork-adattributionkit-ios-app-ads\/","title":{"rendered":"Measuring iOS app ads after ATT: SKAdNetwork, AdAttributionKit and why MMP numbers differ"},"content":{"rendered":"

Updated October 2026.<\/em><\/p>\n

AdAttributionKit is the attribution framework Apple now recommends: the SKAdNetwork documentation page opens with advice to use AdAttributionKit for app campaigns on the App Store and on alternative app marketplaces (Apple Developer, SKAdNetwork<\/a>). Since ATT, measuring iOS app ads relies on two sources: device-level data from users who agree to tracking, and aggregated postbacks from Apple’s two frameworks for everyone else. This article walks through SKAdNetwork and AdAttributionKit, how to set them up with an MMP, how to read numbers that do not match, incrementality testing, a sample conversion value table and a checklist to run before you increase your user acquisition<\/a> budget.<\/p>\n

ATT and the IDFA: the change that started with iOS 14.5<\/h2>\n

Since iOS 14.5, an app must ask permission through App Tracking Transparency (ATT)<\/a> before it tracks users or reads the IDFA<\/a> (the identifier for advertisers). If the user declines, the IDFA returns all zeros (Apple Developer, advertisingIdentifier<\/a>).<\/p>\n

Apple’s User Privacy and Data Use<\/a> page spells out a few points that are often misread. You may not use a hashed email address or phone number to track someone who has not agreed. Session IDs, fingerprint IDs and device graph IDs are also identifiers that need permission. The IDFV may only be used for analytics across apps from the same developer.<\/p>\n

The result: device-level mobile attribution<\/a> now works only for the group that opts in. The group that declines is measured through Apple’s aggregated frameworks, which are slower and less detailed. The APIs of both frameworks can be called without an ATT request (Apple Developer, AdAttributionKit<\/a>). How to ask for permission correctly is covered in our article on Apple’s ATT rules<\/a>.<\/p>\n

SKAdNetwork 4: postbacks, conversion values and crowd anonymity<\/h2>\n

SKAdNetwork<\/a> attributes installs from ads without the IDFA. The current version is 4.0, which runs on iOS 16.1 and later (SKAdNetwork 4 release notes<\/a>).<\/p>\n

1. Three conversion windows<\/strong>, counted from the first app open: days 0 to 2, days 3 to 7 and days 8 to 35. Each conversion window produces at most one postback. Postback 1 arrives after a random delay of 24 to 48 hours; postbacks 2 and 3 arrive after 24 to 144 hours. The app can lock the value to receive the postback sooner, but any later events in that conversion window are then ignored. AdAttributionKit uses exactly the same windows (Apple Developer, AAK conversion windows<\/a>).<\/p>\n

2. Conversion values.<\/strong> The fine value is a 6-bit number from 0 to 63, and it appears only in postback 1. The coarse value has three levels, low, medium and high, and is used in postbacks 2 and 3, and in postback 1 when data is limited (Apple Developer, postback parameters<\/a>). The app decides what each level means.<\/p>\n

3. Crowd anonymity.<\/strong> Version 4 replaces the campaign ID (up to 100 values) with a 4-digit source identifier. Apple assigns each install to a postback data tier based on the crowd size of the app that showed the ad, the advertised app, the country and the source identifier. Fewer installs mean a postback with less information (Apple Developer, Receiving postbacks in multiple conversion windows<\/a>):<\/p>\n\n\n\n\n\n\n\n\n
Tier<\/th>\nPostback 1<\/th>\nPostbacks 2 and 3<\/th>\n<\/tr>\n<\/thead>\n
Tier 3<\/td>\n2 to 4 digit source identifier, fine value, source app, country code<\/td>\n2-digit source identifier, coarse value<\/td>\n<\/tr>\n
Tier 2<\/td>\n2 to 4 digit source identifier, fine value<\/td>\nSame as above<\/td>\n<\/tr>\n
Tier 1<\/td>\n2-digit source identifier, coarse value<\/td>\nSame as above<\/td>\n<\/tr>\n
Tier 0<\/td>\n2-digit source identifier only<\/td>\nNone<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

This table explains a common mistake: splitting iOS spend into too many small campaigns. Each campaign gets few installs, drops to Tier 0 or 1, and loses the fine value entirely. Google Ads also advises limiting the number of iOS campaigns, because many campaigns blur SKAdNetwork data (Google Ads Help, iOS App campaigns<\/a>).<\/p>\n

AdAttributionKit: where it stands in 2026<\/h2>\n

AdAttributionKit (AAK) arrived with iOS 17.4 (early 2024) and measures ads for both the App Store and alternative app marketplaces. Apple Ads help now says “SKAdNetwork is now called AdAttributionKit” (Apple Ads, App ad attribution overview<\/a>).<\/p>\n

Re-engagement: measuring people who already have the app<\/h3>\n

SKAdNetwork cannot measure re-engagement<\/a>. AAK can. A re-engagement counts when someone who already has the app taps a custom-rendered ad, or taps the Open button on a StoreKit-rendered ad (Apple Developer, Receiving ad attributions and postbacks<\/a>). Things to know:<\/p>\n