I am struggling to understand how "Contacts" in Contact Builder interact with the rest of Marketing Cloud.

How do they relate to All Subscribers?

Are they a spendable entity or just a "single view" of all the data relationships?

If I synchronize contact data from Sales Cloud, do I need to do something to associate the records Email Address to the email address of the Marketing Cloud Contact?

2 Answers 2


The Contacts you see in Contact Builder are derived from a number of sources.

  • All Subscribers. All Subscribers creates Contacts with the SubscriberKey used as the ContactKey and the SubscriberID used as the ContactID.
  • Mobile Contacts created by the mobile applications (MobileConnect, MobilePush and GroupConnect). All Contacts created in these apps are added to Contact Builder's Contacts.
  • Sendable Synchronized Data Extensions maintained by Data Stream (Contact_Salesforce, Lead_Salesforce and User_Salesforce). Each distinct _ContactKey in these tables relates to a Contact Builder Contact created behind the scenes. You don't need to do anything to add the records in these tables to Contact Builder.
  • API, where you explicitly create a new Contact directly in Contact Builder using the Contacts REST route.
  • Journey Builder implicitly creates Contacts by API, Data Extension or other event entry source as the records are injected into the interaction.
  • Populations. Yes, Populations still exist for some reason. Defining one of your sendable Data Extensions as a Population automatically creates Contact Builder Contacts.

Contact Builder principally acts as the glue to tie all these sources of data about "Contacts" together into a type of view where you can potentially relate one instance of a contact's data to another across channels and data sources based on their ContactKey. Contacts, themselves, aren't sendable. But you'll find the route each contact took to find its way into Contact Builder, more often than not, was a sendable object - Data Extension or Email/Mobile List.


Those are a lot of questions but most (probably all) are answered in the official documentation. Try this page.

The linked docu page comes up as one of the first results when you google "marketing cloud contacts", by the way. If you already found this page and have trouble with the explanations (which sometimes aren't too clear on specific topics) you should say so and inquire about those specific points you are not sure about.

This makes the question less broad in scope (often a reason for down votes or people putting it on hold) and shows that you tried but got stuck. This is what this community is about after all: providing help when you get stuck after trying.

Pretty much all of us have been at this point once in a while and some now give back for the help they have once been provided. Those people usually don't appreciate it if they feel treated as no-cost freelancer or research assistant. ;)

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