I am building a site that runs an automated process every 30 minutes to match up new flights with their respective user. Once this process is completed I want to email the flight details out to the respective user. However the flight info will be different for every single user with their being 0-300+ potential emails. Is this something that the MailChimp API will allow or do? I found this page http://apidocs.mailchimp.com/api/how-to/transactional-campaigns.php which I am not sure if this effects me. Is the STS more suited to this? http://apidocs.mailchimp.com/sts/1.0/ Thanks Alex