Planhat supports both a one-time push and continuous sync with Mandrill. A one-time sync allows you to filter and select End Users in Planhat and push them to a specific list in Mandrill. Continuous sync creates a mapping between a filter in Planhat and a list in Mandrill, meaning that Planhat will add and remove End Users from the linked Mandrill list as they are added and removed from the linked Planhat filter. Sync occurs at least once every hour.