Subscriber Key

What Is a Subscriber Key

A subscriber key is a text field that contains a value that uniquely identifies a subscriber in your system. If you use a subscriber key, the system uses this value to determine:

• whether a subscriber you import or create already exists in the system.
• whether a subscriber appears multiple times on a list, group, or data extension to be sent a message. This allows an email address to be included multiple times related to different subscriber key values.
• which subscriber record to update when a subscriber accesses their profile center or subscription center.
• which subscriber record to unsubscribe when a subscriber clicks the unsubscribe link in an email.

Note: Though the subscriber key is the unique identifier, ExactTarget currently requires you to provide an email address for each subscriber. Spam complaints are still tied to the email address.

The subscriber key is a text field, so you can enter almost any kind of information in this field. For example, you could identify subscribers by email address, telephone number, or an ID created by an external business system.

You can mix the kind of information you enter in the subscriber key field. For example, you can import subscribers that are keyed on the email address and other subscribers that are keyed on the identifier used in an external business system.

Note: Because the subscriber key can contain different kinds of identifying information, there is the potential that different subscribers with different kinds of keys could coincidentally have the same information. For example, if you import a subscriber keyed on phone number 3175551234 and a different subscriber keyed on external business system identifier 3175551234, the ExactTarget system interprets these as the same subscriber.

Why Use Subscriber Key

Using a subscriber key gives you the ability to identify subscribers with a value that you choose and have a single email address appear in your database multiple times associated to different subscriber keys.

The ExactTarget application interface as well as the AMP SOAP API support functionality around subscribers identified with a subscriber key. The XML API currently does not support the subscriber key.

Scenarios

The Northern Trail Outfitters loyalty program allows families to opt-in together with a single email address. The marketer responsible for the loyalty program wants to send birthday discount coupons for each member in the family.

The marketer uses a subscriber key other than email address. This allows each member of the family to share the email address but have separate subscriber attributes. This also allows the email address to appear on the birthday list multiple times if multiple members of the family have the same birthday.

The Cruz family opts into the loyalty program with the same email address, and the twin daughters have the same birthday.

When the marketer refreshes the birthday group on the twins' birthday, the system collects each unique subscriber key with a DOB value equal to the current date. Even though Lisa and Jill share the same email address, each appears separately in the group.

When the birthday email goes out to the Loyalty Birthday List, Lisa and Jill each receive a separate email to their family's shared address.

How to Import Subscribers with a Subscriber Key

Importing subscribers with a subscriber key value is the same process as importing subscribers without a subscriber key. If the subscriber key data is present, you map the data in your import file to the Subscriber Key field when defining your import.

See the How to Import Subscribers into a List procedure. 

If your organization uses the subscriber key, it is a required field. The Subscriber Key field can contain the same value as the Email Address field.