Use this method to create a new contact or update an existing contact. This method uses the email_address string value you include in the request body to determine if it should create an new contact or update an existing contact.

Updates to existing contacts are partial updates. This method only updates the contact properties you include in the request body. Updates append new contact lists or custom fields to the existing list_memberships or custom_fields arrays.

When this method creates a new contact, it returns a 201 response code.

When this method updates an existing contact, it returns a 200 response code. Updating a deleted contact restores the contact.

The method automatically modifies the contact's permission_to_send and opt_in_source properties depending on the Confirmed Opt-In Constant Contact account setting:

If Confirmed Opt-in is enabled, this method automatically sets the permission_to_send property as pending_confirmation for new contacts.

If Confirmed Opt-in is disabled, this method automatically sets the permission_to_send property as explicit and the opt_in_source property as Contact for new contacts. Updated contacts have their permission_to_send property set as explicit.