User Merging


MoEngage enables you to have a single user ID for all your users even if they are using different devices. The only condition for merging users in MoEngage is that the user has to be signed in on the device.

When a user visits your website or app MoEngage system does the following to merge the user signed in on different devices. 

  • MoEngageID is created for all users as soon as user visit your app or website. (Your app or website need to have MoEngage SDK).
  • ID is set by your app or website to identify users.
    If the ID is:
    • Not created then the user is anonymous. 
    • Created then the user is identified.


When the user visits the website or app for the first time with one device, then the user is called an anonymous user and a MoEngageID is set as MoEID-1 is for that user.

If the user logs in, then this user is an identified user, and an ID called U-1 is set for the user. All events on this device until the user logs out or uninstalls are attributed to MoEID-1.

User 1 using Device 1 MoEngageID ID
Event 1 MoEID-1 -
Event 2 MoEID-1 -
Event 3 MoEID-1 -
Anonymous User logs in New user is registered and ID U-1 is provided by the website or app. This user ID U-1 is linked to MoEID-1.
Event 4 MoEID-1 U-1
Event 5 MoEID-1 U-1
Event 6 MoEID-1 U-1

If the same user visits the same website or app with another device, then this user is still an anonymous user, as MoEngage does not know the identity of this user, and a new MoEngageID is set MoEID-2 is for the user.

If the user logs in, then the website or app notifies MoEngage that the user ID is U-1. Now the anonymous user is merged into the existing user identifier.

User 1 using Device 2 MoEngageID ID
Event 1 MoEID-2 -
Event 2 MoEID-2 -
Event 3 MoEID-2 -
Anonymous User logs in User is identified as U-1 by the website or app. U1 is already linked to MoEID-1. 
Event 4 MoEID-1 U-1
Event 5 MoEID-1 U-1
Event 6 MoEID-1 U-1

User Merge Types

MoEngage provides two types of user merges:

Normal User Merge

When a user logs in and is identified as a previously registered user, the last 100 events prior to log in are also moved to the identified user MoEngageID.
Events performed before these 100 events continue to remain associated with anonymous user MoEngageID. 


Normal User merging is available only in User Profile. 

Universal User Merge

In this approach we have all of the unidentified users mapped to identified users. When we run the query, all the unidentified users are resolved (replaced) with the identified users and we have the right query results.

In the approach, MoEngage does not modify the data.

Old MoEngageID New MoEngageID
MoEID-45 MoEID-13
MoEID-22 MoEID-1



Universal User merging is available only for Key Metrics, Segmentation and Campaign queries. 


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