SKAdNetwork (SKAN): Apple's Privacy-First Advertising Solution for iOS


SKAdNetwork (SKAN) is Apple's privacy-first solution for advertising campaigns on iOS. It became essential with the rollout of iOS 14.5 and the AppTrackingTransparency framework (ATT) in April 2021. SKAN serves as the only way for advertisers to attribute users who have not opted-in, aligning with Apple's privacy guidelines.

Understanding SKAN 4

Conversion Values and Timers

SKAN 4 provides space for 6-bits of downstream metrics, known as a conversion value or SKAN 4 fine grain conversion value. The measurement window for SKAN 3 is 24 hours, while for SKAN 4 Postback 1, it's up to 48 hours. Timers are designed to obscure the time of install, ensuring no link to individual users.

New Features in SKAN 4

Released in October 2022 with iOS 16.1, SKAN 4 introduced several features to enhance advertising capabilities:

Three Measurement Windows

SKAN 4 provides three measurement windows: 0-48 hours, 3-7 days, and 8-35 days, with varying delays for each.

Coarse Conversion Values and Anonymity Tiers

In addition to the original 0-63 fine values, SKAN 4 introduces coarse values (low, medium, high), linked to crowd anonymity tiers, offering more flexibility in measurement.

Source Identifier and lockWindow

The campaign ID has been renamed source ID, functioning hierarchically with up to 10,000 options. The lockWindow feature adds flexibility to measurement window lengths, allowing advertisers to control when postbacks are received.

Web-to-App Attribution

SKAN 4 enables SKAdNetwork attribution from app-to-Safari, a feature previously unavailable.

Measurement Challenges of SKAdNetwork

Less Precision and Delays

SKAN poses significant measurement difficulties, with less visibility into user-level data and metrics. Delays in receiving data also hinder fast optimizations.

Re-Engagement Measurement

As of SKAN 4, re-engagement measurement remains a challenge due to the lack of device- or user-level data collection. However, anticipated changes in the upcoming SKAN 5.0 release are poised to address this limitation.

SKAN 5.0 and Re-Engagement Measurement

In SKAN 5.0, advertisers are expected to measure conversions after a user opens an app by tapping on an ad. This anticipated feature will focus on users who have already installed a specific app, potentially transforming the way re-engagement is measured and understood.While the details are still unclear, and it's not known if re-engagement campaigns will be separate from app discovery campaigns, the anticipated changes in SKAN 5.0 represent a promising development. Advertisers and marketers are eagerly awaiting the launch of SKAN 5.0 to explore the new possibilities it may offer for re-engagement measurement and campaign optimization.

Working with Conversion Values

SKAN 4 introduces three measurement windows with fine and coarse conversion values. Marketers must learn to link their strategic vision to these values to drive growth on iOS.


The evolution to SKAN 4 represents a significant shift in iOS advertising, introducing new features and challenges. Advertisers must adapt to these changes, understanding the complexities of conversion values, measurement windows, and privacy manifests.


  1. What are the main features of SKAN 4?
  2. SKAN 4 includes three measurement windows, coarse conversion values, source identifier changes, lockWindow, and web-to-app attribution.
  3. How does SKAN 4 differ from SKAN 3?
  4. SKAN 4 introduces more flexibility in measurement windows, new conversion value types, and additional features like web-to-app attribution.
  5. What are the challenges with SKAN 4?
  6. Challenges with SKAN 4 include less precision in user acquisition, delays in receiving data, inability to measure re-engagements, and complexities in working with conversion values.
  7. What is the significance of lockWindow in SKAN 4?
  8. lockWindow gives advertisers the ability to apply a 'lock' at any point during the measurement windows, allowing more control over when postbacks are received.

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