SKAdNetwork (also StoreKit Ad Network, often abbreviated SKAN) is Apple’s privacy-friendly system for iOS that lets advertisers measure app installs and certain encoded in-app actions without tracking individual users. While it’s usually talked about from an advertiser’s perspective, it’s just as important for app publishers. The way SKAN evaluates the traffic coming from your app has a direct impact on how advertisers value your inventory. If it signals your app unfavorably (in case your app repeatedly sends low or ‘null’ conversion values, which are numeric scores between 0 and 63 representing a user’s post-install behavior), observed market behaviour suggests that ad budgets can gradually move elsewhere.
Understanding the SKAdNetwork Framework
For years, iOS advertising relied on IDFA-based user-level tracking, which enabled precise attribution, targeting, and retargeting. This collapsed in 2021 with App Tracking Transparency (ATT), because in many markets, a small fraction of users allowed tracking, causing data visibility and optimization accuracy to drop overnight. To address this problem, Apple leaned on its SKAdNetwork system, a privacy-focused tool it had originally introduced back in 2018.
So, how does SKAdNetwork work? The ad network registers the ad with Apple, and your app (the source app) displays it. When a user clicks the ad (SKAN can track installs from ad views, but only if the ad network supports this feature; not all networks do) and installs the advertised app, the app updates a conversion value to indicate what the user did, such as completing a tutorial or making a purchase. Apple then sends an anonymized postback to the ad network, and optionally the developer, showing that the ad led to the install, without sharing personal user or device data. It’s worth noting that postbacks are randomly delayed to protect privacy.
Additionally, a postback from SKAdNetwork is only sent once a campaign or source app achieves Apple’s minimum install requirement. When installs fall short, SKAN may either cancel the postback or issue a “coarse” version that communicates only approximate conversion values, such as low, medium, or high, instead of the precise 0–63 metric.
Why SKAN matters specifically to publishers
SKAN postbacks provide advertisers with aggregated signals about how users from each source-app-id perform after installing the advertised app. Over time, demand-side systems learn which source apps tend to generate higher conversion values. If traffic from your app consistently produces higher CVs, the advertiser’s optimization models assign higher predicted value to your inventory, which typically results in higher bids. Conversely, if users associated with your source-app-id frequently generate low or null CVs, demand-side systems classify your supply as less valuable and decrease bids or reduce spend.
SKAN 4.0, a practical checklist
- Registering for a SKAN ID is the ad network’s job, not the publisher’s. The publisher’s task is to serve the ads and ensure that their app’s Info.plist contains the correct SKAdNetwork IDs used by the networks they work with. This is done by adding an array under the key SKAdNetworkItems in your app’s Info.plist. You can find out more in Apple Developer Documentation;
- Enabling WKAppBoundDomains can disrupt ad delivery because ad SDKs often load content from multiple ad-related domains. If these domains aren’t included in the app-bound list, the web requests fail, and the ads fail to display. Many developers on community forums and blogs have shared practical workarounds, emphasizing that if this feature is used, all ad domains required by the SDK must be whitelisted to ensure proper ad functionality;
- When using Apple’s App Tracking Transparency (ATT) framework, you may prompt users for IDFA access. Even if they decline, SKAdNetwork (SKAN) continues to work, though granting ATT allows for improved targeting.
What lies ahead
As of now, November 2025, Apple is promoting a shift from SKAdNetwork 4.0 to its new AdAttributionKit (AAK) framework, which adds more flexible attribution and re-engagement tracking while maintaining privacy. During this transition, SKAN 4.0 is still widely used and interoperable with AAK, so developers and ad networks often run both frameworks. Partial adoption of AAK is ongoing, meaning the industry is in a period of gradual change rather than an immediate switch.
