- Postmark – email blast and mgmt software for web apps
- Mailgun – mail server API’s for developers
- Postcron – schedule posts on Twitter or Facebook
- Mailjet – bulk and marketing email
- SmtpProvider – bulk email
- JangoMail – marketing and transactional email
- Silverpop – transactional email
- SendGrid – email blast software
- PostageApp – API for transactional emails