I'm trying to send a mail from email FROM_EMAIL to TO_EMAIL using PHP and Mailchimp API using just a POST request.
Mailchimp offers a marketing campaign API for sending emails in bulk from one sender to many recipients. However, I'm wondering if Mailchimp also provides an option for sending one-to-one emails from a sender to a specific receiver, like some other email API clients do. Am I just overlooking this option in Mailchimp?