Aritic Mail - Ariticmail is a transactional email delivery API for applications and enterprises.
Amazon SES - Scale your business email & marketing messages with Amazon Simple Email Service (SES), a cost-effective and reliable cloud email service. Sign up today.
Vero - Email platform for product, marketing and engineering teams
Mailgun - A set of powerful APIs that enable you to send, receive and track email from your app effortlessly whether you use Python, Ruby, PHP, C#, Node.js or Java.
RealTime Email - RealTime Email provides email relevance by enabling marketers to respond to each recipient’s personal context.
Mandrill - Mandrill is a new way for apps to send transactional email. It runs on the delivery infrastructure that powers MailChimp.