# RevenueCat: Setting Universal Identifiers

A common question we see with [RevenueCat ](https://www.revenuecat.com/)users is how to link back a universal ID to link the subscription or consumable event with an identifiable user on other data sources.

For both Android and iOS we recommend you send along with all IDs available to expand your options on aliasing with other data sources. This will require you to set some **Subscriber Attributes** in the app.

### Android <a href="#h-android" id="h-android"></a>

On Android, use the **collectDeviceIdentifiers** function to set the GAID as a subscriber attribute: [RevenueCat documentation.](https://sdk.revenuecat.com/android/purchases/com.revenuecat.purchases/-purchases/collect-device-identifiers.html)

### iOS <a href="#h-ios" id="h-ios"></a>

Use [**collectDeviceIdentifiers**](https://sdk.revenuecat.com/ios/Classes/RCPurchases.html#/c:objc\(cs\)RCPurchases\(im\)collectDeviceIdentifiers) to automatically set the device identifiers as subscriber attributes ([revenueCat Github](https://github.com/RevenueCat/purchases-ios/blob/3.10.7/Purchases/Public/RCPurchases.h#L531)).

Questions about [user-level policy adherence](https://docs.adlibertas.com/privacy-and-security/privacy-and-security-details)?
