SKAdNetwork (SKAN)

SKAdNetwork (SKAN, StoreKit Ad Network) is Apple’s API that tells ad networks which ad led to an iOS app install without revealing who installed it. Results come back as postbacks signed by Apple, with a delay and with no user or device data.

What is SKAdNetwork?

SKAdNetwork has been around since iOS 11.3. Since ATT took effect in 2021, it has been the main way to measure installs from users who don’t consent to tracking. Apple states plainly that apps don’t need ATT permission before calling this API. Three parties are involved (Apple Developer, SKAdNetwork, accessed October 2026):

• The ad network: registers with Apple to get an ad network ID, signs ads and receives postbacks.
• The app that displays the ad (source app): lists the ad networks’ IDs in its Info.plist.
• The advertised app: updates its conversion value as the user opens the app and keeps using it.

Users have 30 days to install the app after tapping an ad, or 24 hours if they only saw a view-through ad. One ad network receives the winning postback, and up to five others receive “non-winning” postbacks.

What did SKAdNetwork 4 and AdAttributionKit change?

SKAdNetwork 4 runs on iOS 16.1 and later (released October 24, 2022). The biggest change is three conversion windows counted from the first app open: days 0 to 2, days 3 to 7 and days 8 to 35, with up to three postbacks for a winning install (Apple Developer, SKAdNetwork 4 release notes, accessed October 2026). This version also added:

• A fine-grained conversion value (fine value, 0 to 63) available only in the first postback, and a coarse value (low, medium, high) for later postbacks or when there are too few users.
• A hierarchical 4-digit source identifier in place of the campaign ID. A postback gets 2, 3 or 4 digits depending on the crowd anonymity tier Apple calculates.
• Measurement for ads shown in Safari.

The first postback arrives at a random time 24 to 48 hours after its window closes; the second and third arrive after 24 to 144 hours. Apple lets you lock the value early to get the postback sooner.

Starting with iOS 17.4 (March 2024), Apple added AdAttributionKit. The SKAdNetwork page now points developers to AdAttributionKit for campaigns on the App Store and on alternative app marketplaces. According to Apple’s updates page, AdAttributionKit added re-engagement measurement in June 2024, then in June 2025 let apps set their own attribution windows and receive country codes in postbacks (Apple Developer, AdAttributionKit updates, accessed October 2026).

Example

Hypothetical: an e-commerce app uses the 6 bits of the fine value to bucket the revenue of the first order within 2 days, for instance value 10 for orders under VND 200,000 and value 40 for orders over VND 1 million. For the coarse value, the marketing team decides that low means account sign-up, medium means add to cart and high means purchase. These values carry no built-in meaning; the app defines them. The mapping table can live in your MMP so every ad network reads it the same way.

How is SKAdNetwork different from AdAttributionKit?

The two frameworks share the same ad network IDs. When an app has impressions from both, the system ranks them together and picks just one winner: clicks always beat views, then the most recent wins, with up to 6 impressions considered (Apple Developer, AdAttributionKit and SKAdNetwork interoperability, accessed October 2026).

Frequently asked questions

Should you drop SKAdNetwork and move entirely to AdAttributionKit?

You don’t have to choose yet. Apple lets you call both APIs, and the system passes SKAdNetwork conversion value updates through to AdAttributionKit. Ask each ad network which framework it uses to sign ads.

Why are SKAdNetwork install numbers lower than App Store Connect’s?

SKAdNetwork only counts installs tied to a signed ad and opened within the time limit. Organic installs get no postback.

If you need to rebuild the conversion value mapping for your iOS campaigns, Adtek’s App User Acquisition team can work through it with you via the contact page.