What is a List key?

What is a List key?

List key is used to add contacts to a mailing list via API method. It is used as an authentication parameter and represents the mailing list you're trying to access.
To view list key
  1. From the  Navigation  toolbar, choose Contacts and select Manage Lists.
  2. Click on the required list.
  3. Select Setup to view the list detail. You will find the list key in this tab.list key