Unique Identifier
Rikke Søndergaard avatar
Written by Rikke Søndergaard
Updated over a week ago

Unique Identifier


In this Articles


What is Unique Identifier

A Profile is identified by something unique that will separate them from other Profiles - we call that unique thing a Unique Identifier. You can use:

  • Email

  • Mobile Number

  • or CRM ID

The Unique Identifier is used by to understand which Profile to merge and which to keep apart. To avoid duplicates and keep data relevant the system merges Profiles that can be confirmed to belong to the same individual, while keeping Profiles that have different owners separate.


Which Unique Identifier to Choose?

Depending on the nature of your business, data structure and business goals you can choose to use either one.

Using Email as Unique Identifier

Efficy Marketing is by default set to use email as Unique Identifier. In many cases the email address of a Profile is used as the unique identifier since it’s usually quite unique to a person. Using the email is a good choice but be aware that Profiles will only be able to have one email as the Unique Identifier.

A profile can have many emails as Attributes, but only one email as unique identifier.

Using Mobile Number as Unique Identifier

The principle from email also applies to using Mobile as a Unique Identifier.

Using a CRM ID as a Unique Identifier

Using Email or Mobile Number as Unique Identifier means that in order to be identified, Profiles were limited to only one email address or phone number.

A Profile with a CRM ID as their Unique Identifier can contain a shared email address or phone number. Whereas Profiles using the same email address or phone number would usually be merged, these Profiles imported from the CRM would contain both email addresses or phone numbers, allowing Profiles to receive personalized communications via a shared address.

Additionally, any CTAs or links that the email recipient clicks in a shared device will register in their individual Profile only and will not be shared across other Profiles with the same email address or phone number.

How Does it Work?

Let's imagine that two of your subscribers, a happily married couple, share the same email address.

Using this email address to consent to your communications and sign-up to your Subscription, they both create Profiles in your CRM.

Now there are two Profiles in your CRM and APSIS One Audience that share the same email address.

In your next email marketing campaign, create a personalized email with Data Tags to display the recipients name, or add Row Segmentation.

Both Profiles will receive a personalized email addressed to them, containing content they consented to receive.

One email address, two recipients, two different emails!

A Note on CRM IDs...

Unique identifiers like email address and phone number can no longer be used to search for Profiles that have been imported from a CRM integration.

To search for Profiles imported from the CRM integration, use the CRM ID belonging to the Profile you wish to search for.


Switch Unique Identifier

Profiles consist of a Key Space and a Profile Key. Any given Profile can have multiple Profile Keys however each of them must belong to a different key space. This feature allows to remove one of the current Profile Keys from an existing Profile and replace it with another new Profile Key within a different Key Space.

How to Switch Unique Identifier

Let’s imagine James who has an email that identifies him. Now, you decide that it’s better for the data structure to identify him by CRM ID.

This mean James will no longer be identified by his email. However, it’s vital to keep all his historical event data such has consents, website interactions and response data.

Use the APSIS One API (only single Profile)

Watch this video to learn how to Change the Unique Identifier for a single Profile with API.


What's Next?

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