1. All-in-one email service provider that provides maximum insight and deliverability results for both marketing and transactional emails.

  2. 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.

  3. Doppler Relay guarantees the arrival of the Emails and allows to access detailed analytics in real time.

  4. JangoSMTP is a transactional email delivery service that adds tracking and authentication to email.

  5. TotalSend allows businesses to centralize their transactional and marketing communications across email and SMS.

  6. Email sending library for PHP.

  7. Learn why more developers choose SendGrid for their email deliverability service to send transactional emails triggered by web apps. Get started for free

  8. Open source mail delivery platform, alternative to Mailgun or Sendgrid

  9. PostageApp is an email management service that makes it easy to design, deliver, and manage all of the email that websites or applications send.

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

  11. Postmark is the easiest and most reliable way to be sure your important transactional emails get to the inbox. Simply & reliably parse recieved email to JSON for your webapp.

  12. GreenArrow Transactional Email provides a flexible and secure SMTP and API email delivery from application or website.