CertainSource is the industry leader in email subscriber acquisition, providing email marketers with new-to-file subscribers that perform as well or better than their house files. CertainSource’s ListBuilder platform not only performs the most rigorous email address cleansing process in the industry, it also tracks email engagement and transactions of the new-to-file subscribers added to client databases. This tracking enables CertainSource to continuously optimize at the click source of these new subscribers so the subscribers you buy from CertainSource tomorrow perform even better than those you buy today. If your goal is building a high performing email list, safely and at scale, CertainSource is your partner.