Nope! Our system will automatically ignore duplicate email addresses.
If you add or import the same email address twice, we will only keep one instance of the email address in the system. However, if you’ve updated details about that contact (name, contact info, etc) and re-import it, that information will update without duplicating the email address.
If you have one email address on multiple lists, and you send a campaign to all of those lists, the contact will only receive one copy of your campaign.