This library written in Ruby provides integration between the SendGrid SMTP API and ActionMailer. The SendGrid SMTP API allows developers to deliver custom handling instructions for email. SendGrid is an email application.
Ubivox, email marketing service, has released a number of its features via the Ubivox API. Ubivox allows marketers to create, track, and manage email marketing campaigns directly in a web browser. Because Ubivox is web-based, no additional software becomes necessary to create top notch campaigns. From simple email marketing to tips, to enterprise grade web based software tools, Ubivox aims to be the go to newsletter partner.