What is Crowd Anonymity?
To protect user privacy, Apple limits the data in SKAdNetwork postbacks based on crowd anonymity. The idea is simple: the more installs a campaign generates, the harder it is to identify any individual user, so Apple shares more data. Apple assigns each app download a postback data tier (0-3). Higher tiers = more data.How Apple Determines Your Privacy Tier
Apple calculates your tier based on:- Crowd size of the app/domain displaying the ad
- Crowd size of the advertised app
- Country where the app was installed
- Hierarchical source identifier provided by the ad network
What Data You Receive at Each Tier
| Field | Tier 0 | Tier 1 | Tier 2 | Tier 3 |
|---|---|---|---|---|
| source-identifier | 2 digits | 2 digits | 3 digits | 4 digits |
| conversion-value (fine) | ❌ | ❌ | ✅ | ✅ |
| coarse-conversion-value | ❌ | ✅ | ✅ | ✅ |
| source-app-id / source-domain | ❌ | ❌ | ❌ | ✅ |
| country-code | ❌ | ❌ | ❌ | ✅ (if crowd size qualifies) |
Tier 3 (Best Data)
- Full 4-digit source identifier
- Fine-grained conversion value (0-63) in first postback
- Coarse conversion value in all postbacks
- Source app ID or source domain
- Country code (if crowd size qualifies)
Tier 2
- 3-digit source identifier
- Fine-grained conversion value (0-63) in first postback
- Coarse conversion value in all postbacks
Tier 1
- 2-digit source identifier
- Coarse conversion value only (Low/Medium/High)
- No fine-grained conversion value
Tier 0 (Minimal Data)
- 2-digit source identifier
- No conversion value data
- Only confirms an install happened