Postmark - 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.
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.
SendGrid - Learn why more developers choose SendGrid for their email deliverability service to send transactional emails triggered by web apps. Get started for free
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
JangoSMTP - JangoSMTP is a transactional email delivery service that adds tracking and authentication to email.
Constant Contact - Constant Contact offers email marketing, social media marketing, online survey, event marketing, digital storefronts, and local deals tools.