Brevo - Innovative online Email Marketing solution to manage your contacts, create & send your newsletters and track your results. More than 80 000 clients. Best prices and attractive features.

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

Litmus - litmus tests and tracks your email campaigns, so you can always put your best design forward.

mailcow - An open source mailserver suite.

Return Path - Inbox placement solutions from Return Path helps improve email deliverability and increases email marketing ROI.

Mail-in-a-box - 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.