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9 self-hosted alternatives to Courier MTA (2026)

Fast, scalable, enterprise mail/groupware server providing ESMTP, IMAP, POP3, webmail, mailing list, basic web-based calendaring and scheduling services.

License: GPL-3.0 · Language: C/deb source code

chasquid source

SMTP (email) server with a focus on simplicity, security, and ease of operation.

Apache-2.0Go

DragonFly

A small MTA for home and office use. Works on Linux and FreeBSD.

BSD-3-ClauseC

EmailRelay source

A small and easy to configure SMTP and POP3 server for Windows and Linux.

GPL-3.0C++

Exim source

Message transfer agent (MTA) developed at the University of Cambridge.

GPL-3.0C/deb

Haraka source

Fast, highly extensible, and event driven SMTP server.

MITNodejs

OpenSMTPD source

Secure SMTP server implementation from the OpenBSD project.

ISCC/deb

Complete trashmail solution that exposes an SMTP server and has a web interface to manage received emails. Works with multiple and wildcard domains and is fully file based (no database needed). Includes RSS feeds and JSON API.

Apache-2.0Python/PHP/Docker

Postfix

Fast, easy to administer, and secure Sendmail replacement.

IPL-1.0C/deb

Sendmail

Message transfer agent (MTA).

SendmailC/deb

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