Setting the Customer User ID

Optional

The Customer User ID (CUID) is a unique user identifier created outside the SDK by the app owner. If made available to the SDK, it can be associated with installs and other in-app events. These CUID-tagged events can be cross-referenced with user data from other devices and applications.

Set the CUID

To set the CUID:

[AppsFlyerLib shared].customerUserID = @"my user id";

AppsFlyerLib.shared().customerUserID = "my user id"

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Note
The Customer User ID must be set with every app launch.

Associate the CUID with the install event

If it’s important for you to associate the install event with the CUID, you should set to set the customerUserId before calling the start method. This is because start sends the install event to AppsFlyer. If the CUID is set after calling start, it will not be associated with the install event.

- (void)applicationDidBecomeActive:(UIApplication *)application {
  	// Your custom logic of retrieving CUID
    NSString *customUserId = [[NSUserDefaults standardUserDefaults] stringForKey:@"customerUserId"];  
    if (customUserId != nil && ![customUserId  isEqual: @""]) {
        // Set CUID in AppsFlyer SDK for this session
        [AppsFlyerLib shared].customerUserID = customUserId; 
        // Start
        [[AppsFlyerLib shared] start]; 
    }
}

func applicationDidBecomeActive(_ application: UIApplication) {
  //  your logic to retrieve CUID
  let customUserId = UserDefaults.standard.string(forKey: "customUserId") 
  
  if(customUserId != nil && customUserId != ""){
     // Set CUID in AppsFlyer SDK for this session
    AppsFlyerLib.shared().customerUserID = customUserId    
    AppsFlyerLib.shared().start() // Start
  }
}