Identity merge is an overhaul of Mixpanel's identity management capabilities. We've made drastic improvements to our identity resolution infrastructure and added new tools to give users more power and transparency in mapping user actions together. These improvements are available without the need for any code changes to existing implementations - simply enable Identity Merge and ensure your SDK version is up to date to receive the benefits.
This article covers the improvements to Mixpanel's identity management infrastructure, how to check if your project has Identity Merge enabled, and the changes you can expect when the new system is enabled.
Benefits of the New System
The new system improves the behavior of identify(), alias(), and adds a new event called $merge.
All pre-authentication activity can now be mapped back to a user
The ID merge system makes it possible to link pre and post authenticated event streams under a single identifier. This eliminates “false-uniques”, ensuring the most accurate conversion and drop-off rates in funnels and flows.
Previously, Mixpanel could only map pre-sign up activity back to a user who was later identified. Any activity a user did anonymously before signing in again could not be attributed to that user.
Merge data with different unique identifiers
Mixpanel can now merge events with different unique identifiers. The existing identify and alias methods along with the new $merge event can now be used to merge event streams under a single user, even after data has been ingested.
Easier implementation while remaining backward compatible
Those with Mixpanel already implemented will not need to change anything in their implementations. The identify and alias methods already implemented will be able to merge identifiers as soon as the ID merge system is enabled.
For new implementations, the updated functionality of the identify method makes implementation easier. Just call identify with your chosen identifier as soon as you know who the user is to merge anonymous and identified distinct_ids. Calling alias on sign up is no longer required.
Enable ID Merge
You can see if your project has ID merge enabled by checking Identity Merge under Project Settings.
You can request for your organization to be added to the ID merge system via Organization Settings in the Identity Merge tab. This will turn ID merge on for all projects in your organization.
For client-side implementations, make sure your SDK version is up to date so ID merge is able to link pre-authentication activity back to an authenticated user. ID merge is supported with:
- iOS - obj: 3.4.7+
- iOS - swift: 2.6.3+
- Android: 5.6.3+
- Unity: 2.0.0+
Changes After Enabling ID Merge
An email will be sent to the user who enabled ID Merge when the migration is complete. You can expect the following changes after completion:
New events will show up in your project
Mixpanel will track new $identify and $create_alias events when necessary when the identify and alias methods are called respectively in your implementation. These events (and $merge) do not count towards billing. By default, these events will be hidden from dropdowns. You can choose to unhide them in Lexicon.
Unique user counts may decrease, user profile counts may decrease
Since ID merge can merge already ingested events together under a single user, you may notice a change in the unique counts of events in your project. If a user profile exists for multiple distinct ids that are merged, Mixpanel will hide all but one of the user profiles.
Reports will take some time to reflect merged identifiers
The Activity Feed within Explore will show different distinct_ids as being merged immediately. Unique counts in other Mixpanel reports like Funnels, Insights, and Cohorts will take up to 4 hours to properly reflect the merged state of identifiers.
Monthly Tracked User (MTU) tallies may decrease
The MTU billing system is based on the number of users you track with Mixpanel. Since ID Merge is able to map user activity together more effectively, you may notice a decrease in your MTU count. Note: Previously months billing tallies will not be modified.
You can no longer control the canonical id for users in Mixpanel
The ID merge system will now determine which distinct_id is used as the canonical id for a user in Mixpanel. Any merged id can be used to query for information about a user with our APIs, but the results of the query may return a with different distinct_id value than the one used in the query. The id that is returned is the canonical id determined by Mixpanel for that user.
To ensure the queried id is available in the results, it is best practice to send your chosen user id in as an explicit property for events and profiles.
Avoid using non-Mixpanel generated anonymous ids
The updated identify method comes with some built-in guardrails to help avoid users sharing a device from being incorrectly merged together. These guardrails require that anonymous activity is tracked with a distinct_id using a UUID v4 format (distinct_ids generated by Mixpanels client-side SDKs meet this requirement). Tracking anonymous activity with Mixpanel generated distinct ids will allow for correct merging behavior once a user is identified. Note: We’ve worked Segment to ensure their anonymous ids are also compatible with our new system.
User profiles will not automatically aggregate all user properties when merged
This will mainly affect implementations that have duplicate or anonymous user profiles.
ID merge will map events from merged ids together. When this happens, Mixpanel will display the profile with the Mixpanel determined canonical id. User property values will not be updated or added based on other profiles merged. To avoid losing profile properties, we recommend creating user profiles after a user has been identified.
Distinct_ids cannot be un-merged
Merged distinct IDs cannot be unmerged.
Testing ID Merge
If you want to test the ID Merge system before enabling it in your primary organization, the easiest method is to create a new test organization. All organizations created after March 16th, 2020 will have identity merge enabled by default for all projects.
To create another organization you will need to sign up for a new Mixpanel account. After making a new account, create a project and invite any other users who want to test the id merge system to the project. Any data sent to the new project will follow the identity merge rules, giving the ability to test the new id merge behavior without affecting your primary organization's data.