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.
SpamAssassin - Use this program to "Unspam" your mailbox(es).
Litmus - litmus tests and tracks your email campaigns, so you can always put your best design forward.
MailScanner - MailScanner is a open source email security system design for Linux-based email gateways.
Return Path - Inbox placement solutions from Return Path helps improve email deliverability and increases email marketing ROI.
Rspamd - Rspamd is an advanced spam filtering system that allows evaluation of messages by a number of rules...