Unify FAQs

Yes, Identity Graph supports multiple external IDs.

Identity Graph automatically collects a rich set of external IDs without any additional code:

1. Device level IDs (for example, anonymous_id, ios.idfa, or android.id)
2. Device token IDs (for example, ios.push_token or android_push_token)
3. User level IDs (for example, user_id)
4. Common external IDs (for example, email)
5. Cross-domain analytics IDs (for example, cross_domain_id)

If you want Identity Graph to operate on a different custom ID, you can pass it in using context.externalIds on an Identify or Track call. If you're interested in this feature, contact your CSM to discuss the best way to implement this feature.

Segment analyzes each incoming event and extracts external IDs (like user_id, anonymous_id, email). The simplified algorithm works as follows:

1. Segment first searches the Identity Graph for incoming external IDs.
2. If Segment finds no matching profile(s), it creates one.
3. If Segment finds one profile, it merges the incoming event with that profile. This means that Segment adds the external IDs on the incoming message and resolves the event to the profile.
4. If Segment finds multiple matching profiles, Segment applies the identity resolution settings for merge protection. Specifically, Segment uses identifier limits and priorities to add the correct identifiers to the profile.
5. Segment then applies limits to ensure profiles remain under these limits. Segment doesn't add any further merges or mappings if the profile is at either limit, but event resolution for the profile will continue.

All Profile matching is deterministic and based on first-party data that you've collected.

Segment doesn't support probabilistic matching. Most marketing automation use cases require 100% confidence that a user is who you think they are (sending an email, delivering a recommendation, and so on). The best way to support this is through a deterministic identity algorithm.

If two merged user profiles contain conflicting profile attributes, Segment selects the newest, or last updated, attributes when querying the profile.

Any of the external IDs can be used to query a profile. When a profile is requested, Segment traverses the merge graph and resolves all merged profiles. The result is a single profile, with the latest state of all traits, events, and identifiers.

No. As the Identity Graph uses external IDs, they remain for the lifetime of the user profile.

No. Alternatively, you may delete the entire user profile from Segment using a GDPR deletion request.

Segment determines the Monthly Tracked Users (MTUs) count by the number of unique user IDs and anonymous IDs processed, regardless of how you manage these profiles in Unify and Engage. This count is taken as events are sent to Segment, before they reach Unify and Engage. Therefore, the creation of new profiles or the merging of profiles in Unify doesn't affect the MTU count. The MTU count only increases when you send new unique user or anonymous IDs to Segment.

The Profile Explorer retains event details for a period of up to 2 weeks. If you need event information beyond this timeframe, Segment recommends using Profiles Sync for comprehensive event analysis and retention.

Yes, you can remove a trait from a user profile by sending an Identify event with the trait value set to null in the traits object from one of your connected sources. For example:

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{
2
  "traits": {
3
    "trait1": null
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  }
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}

Setting the trait value to an empty string won't remove the trait, like in this example:

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{
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  "traits": {
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    "trait2": ""
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  }
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}

Instead, this updates the trait to an empty string within the user profile.