You will likely need to bulk-import contacts into your Engage enviroment, when starting up your Engage account, or migrating, or when updating certain data points.There are a number of ways this can be done. Each has its own dedicated article.
When you have a small customer database of less than 500 000 records, manual import by CSV is the recommended way to import (or update) those contacts.
For customer databases of 500 000 records or more, it is recommended to use the XML-importer. This is a more automated process where you export your contacts from your own database as XML files that are then placed on the Engage FTP server. From here they are imported by a scheduled job.This method has better high volume performance and superior error management.For this to work, the “ContactXmlImporter” module setting needs to be activated by your Engage team.