SKAdNetwork: SKAdNetwork (SKAN).

Since App Tracking Transparency arrived in 2021, iOS apps must ask permission before tracking users across other companies' apps. Most users say no. SKAdNetwork is how advertisers still learn which campaigns drove installs, without learning who installed.

How SKAdNetwork works

1. The ad is signed. When an ad network shows an ad for your app, it attaches a cryptographic signature with its network ID, a campaign or source identifier, and the app being advertised.
2. The user installs and opens the app. The device, not a server, records that the install came from that signed ad.
3. The app updates a conversion value. As the player does things you care about (finishes the tutorial, reaches a level, makes a purchase), your app or your MMP SDK updates a number that encodes that progress.
4. The device sends postbacks later. After a timer and a random delay, the device sends the ad network an attribution postback. It contains the campaign information and the conversion value, but no device ID and no user data.

The ad network, and usually your MMP, then aggregates these postbacks into campaign reports.

SKAN 4 postbacks and conversion values

SKAdNetwork 4 sends up to three postbacks per install, each covering a window of time after install:

Postback	Window after install	Conversion value it can carry
1	Days 0 to 2	Fine (0 to 63) or coarse
2	Days 3 to 7	Coarse only
3	Days 8 to 35	Coarse only

• Fine values are 64 possible numbers (0 to 63), so you can encode quite detailed early behaviour.
• Coarse values are just low, medium or high. Apple sends "none" if none of your conditions was met.
• Crowd anonymity. Apple decides how much detail to include based on how many installs a campaign has. Small campaigns may get coarse values or fewer source-ID digits instead of the full data.
• Lock window. You can end a window early to receive the postback sooner, which helps when you need faster signals.

A worked example: mapping conversion values

A puzzle game sets its coarse values like this:

Coarse value	Condition
Low	Finished the tutorial
Medium	Reached level 10
High	Made any purchase

A campaign produces 1,000 first-window postbacks: 400 low, 150 medium, 50 high and 400 none. The team estimates:

• Tutorial completion or better: (400 + 150 + 50) ÷ 1,000 = 60%
• Purchase rate in the first days: 50 ÷ 1,000 = 5%

Compared with another campaign at 2% high, this one is likely bringing more valuable players, even though neither report names a single user. Teams then combine these signals with their cohort analysis and modelling to estimate ROAS and LTV by campaign.

What is AdAttributionKit?

AdAttributionKit is Apple's newer attribution framework, introduced in 2024. It follows the same privacy model as SKAdNetwork and is designed to be interoperable with it. It adds support for apps distributed through alternative app marketplaces in the EU and for re-engagement attribution (measuring ads that bring existing users back). Many teams run both frameworks during the transition. Check Apple's developer documentation for the current windows and features, as they continue to change.

Practical tips

• Design your conversion schema first. Decide which early events best predict long-term value in your game. That usually means the first purchase, ad views and progress through the first levels.
• Let your MMP manage it. Most MMPs offer conversion value schemas and decode postbacks into readable reports.
• Accept the delay. Postbacks arrive days after install. Do not judge an iOS campaign on day one.
• Keep campaigns big enough. Splitting spend into many small campaigns can push them under Apple's privacy thresholds and leave you with less data.

See our ads and user acquisition service if you want help setting up iOS measurement.