The Campaign Events service provides access to the detailed results (Open, Click, Bounce and other Events) associated with any Campaign (email) sent in the last 90 days. It helps answer these kinds of question: What Contacts Opened my last email? What links in the Campaign did they Click On? When did the Contact perform the action?

Constant Contact provides API's that allow you to get details of email campaigns, to create an email campaign based on custom HTML code, and to update details of email campaigns. You can get a list of campaigns, and query individual campaigns to get more details for each one. 

An active contact belongs to one or more contact lists, and there are two ways to manage subscriptions of contact lists.  To manage a particular contact's subscriptions, you have to modify the contact information directly.  Each contact's information contains a list of contact lists to which the contact has subscribed, and by modifying this list, you can manage the contact's list subscriptions.

Contact lists are at the heart of the Constant Contact data model. The Constant Contact REST API provides developers with several method to work with contact lists, enabling list creation, list reading and list updating.

The Constant Contact APIs allow you to manage contacts in your account in various ways.  By utilizing contacts collection and resource, you can add, edit, unsubscribe contacts as well as modify their contact list memberships.

V1 Documentation & V1 Libraries

To find particular contacts by email addresses, you can query the contact collection with a query parameter.

The contact list subscriptions are described in <ContactLists> element of a contact's details.  Each contact list to which the contact has subscribed is described in <ContactList> element inside <ContactLists>.

To remove a contact from all lists, you need to start with the contact's detail data and simply remove all of the <ContactList> elements from the <ContactLists> element, and issue the PUT method on the contact resource.

A Contact is opted-out by issuing the DELETE method on the contact resource.