A Monthly Active Contact (MAC) is a billing metric that we apply to MessageBird customers who use Inbox.

We classify a Monthly Active Contact (MAC) as a single end-user who has had one or more interactions with a MessageBird Inbox customer on one of MessageBird’s communication channels during a single calendar month.

MACs are identified by unique channel identifiers, such as:

• Email address
• SMS-enabled number
• Voice-enabled number
• Chat identity

A single end-user may be counted as multiple MACs when they interact via several channels, and their channel identifiers are not part of the same contact profile. 

We classify an interaction as one of the following:

• A single one-way communication from the MessageBird Inbox customer to the end-user
• A response from the MessageBird Inbox customer to the end-user during two-way communication