1. Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.

  2. Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.

  3. Scale your business email & marketing messages with Amazon Simple Email Service (SES), a cost-effective and reliable cloud email service. Sign up today.

  4. PowerMTA is an industrial-strength software for high-volume email delivery.

  5. Mandrill is a new way for apps to send transactional email. It runs on the delivery infrastructure that powers MailChimp.

  6. Sendmail is a general purpose internetwork email routing facility that supports many kinds of...

  7. Mail-in-a-Box provides webmail and an IMAP/SMTP server for use with mobile devices and desktop mail software and also includes contacts and calendar synchronization.

  8. The Courier mail transfer agent (MTA) is an integrated mail/groupware server based on open...

  9. OpenSMTPD is a FREE implementation of the server-side SMTP protocol as defined by RFC 5321, with...

  10. A small Mail Transport Agent (MTA), designed for home and office use. Part of ...

  11. netCORE offers software solutions for digital marketing and communications needs.

  12. 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.