What is the difference? Contact Key vs Contact ID vs Subscriber Key ?

What is the difference between Contact Key, Subscriber Key and Contact ID in Salesforce Marketing Cloud

If you are user of Salesforce Marketing Cloud, or managing a project that deals with Salesforce Marketing Cloud, you may hear these terms from the tech and developer teams.

  • Contact Key
  • Contact ID
  • Subscriber Key

All of these sounds familiar, and seems to point the same thing, right? I bet you know the answer, these are all related to Contact Data in Salesforce Marketing Cloud.

Let’s look one by one.

Contact Key

This is a unique identifier of the contact, that is related to different channels. So, a single contact key works between the contact itself, the channels and the relationship. The Contact Key is the same for the contact among multiple (different) channels.

Imagine that one of your contact is in your email channel. There is a specific identifier for the contact in email channel, for instance email address (I know what technical architectures think, just assume the simplest case). Then, this contact is also in one of our text message list. This channel uses the mobile phone number as a specific identifier.

As a marketing manager, you want to be consistent among these two channels. You do not want the same person to get an email and text message for the same message.

The Contact Key gives you this ability and consistence. Existence of the contact key gives you the consistence of sending messages thru multiple channels and identify your contacts. Email and Text Message channels in our case.

Contact ID

Contact ID is a unique number for your contacts in Salesforce Marketing Cloud. This number helps uniquely identifying the contact on the back-end system. This is an application level number thru the entire Marketing Cloud system.

Subscriber Key

This is the most known key among marketers. Subscriber Key identifies the contacts in the Email Studio. Since email is the most used communication channel, Email Studio is the most used app in Salesforce Marketing Cloud. I have never seen anyone who does not heard about the Subscriber Key.

What are the benefits of Subscriber Key ?

  • Maintains uniqueness of a single separate contact among all subscriber attributes. (For instance, if two of your contacts use exactly the same email address, you can maintain two different set of subscriber attributes to these persons.) It sounds confusing, let me give a specific real life example. Lets think a wife and a husband shops for different products from your store. Wife purchases and has an interest on kitchen appliances. The husband purchases and has an interest on tech products. They share the same email address. You know, they use the same email, but they want to get marketing emails according to their interests. Yes, you bet, Subscriber Key helps you to identify these two persons.
  • Sometimes, a single person may need to get a single communication message for multiple emails he/she owns. You may have both business email address and personal email address of a person. If you want to send marketing messages only on his/her personal email. Then, you need to identify this person on Subscriber Key.

Subscriber Key decision depends on the business purposes. The Subscriber Key must be consistent among all your entire marketing operations.

And keep in your mind, good Marketing Cloud experts never use the email address as Subscriber Key.

Hope this article helped you understanding the differences between Customer Key, Contact ID and Subscriber Key. If you liked my article, please share it with your Social Media, please feel free to write your comments below.