If you setup your templates in mailchimp/mandrill, you can use their API to send transactional email templates with plug-in variables at a specific time (send_a

If you setup your templates in mailchimp/mandrill, you can use their API to send transactional email templates with plug-in variables at a specific time (send_at) parameter. Basically, for example, new user drip campaign might be 5 emails, 1 a day, after signing up. You create the 5 templates, when user signs up, you initiate the 5 transactional emails with send_at datetime parameter +1 day for each. This automatically schedules the emails to go out from mandrill/mailchimp's side, and your app can forget about it. You just have to make the email templates. Integrate with their webhooks, and you can track when the emails are sent, open, etc..