Software Alternatives, Accelerators & Startups

OpenSMTPD

OpenSMTPD is a FREE implementation of the server-side SMTP protocol as defined by RFC 5321, with...

Some of the top features or benefits of OpenSMTPD are: Simplicity, Security-focused, Lightweight, Integration with OpenBSD, and Active Community. You can visit the info page to learn more.

Best OpenSMTPD Alternatives & Competitors in 2025

The best OpenSMTPD alternatives based on verified products, community votes, reviews and other factors.
Filter: 12 Open-Source Alternatives. Latest update:

  1. 23

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

    /postfix-alternatives
  2. 16

    sSMTP is a simple MTA to deliver mail from a computer to a mail server.

    /ssmtp-alternatives
  3. The #1 email warming service to improve your deliverability by generating realistic and meaningful engagement to your emails. Easy-to-use solution to help you land in the main inbox instead of the spam folder.

    Visit website paid $19.5 / Monthly (Pro)

    Visit website
  4. 19

    Sendmail is a general purpose internetwork email routing facility that supports many kinds of...

    /sendmail-alternatives
  5. 18

    Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.

    Open Source

    /exim-alternatives
  6. 11

    msmtp is an SMTP client.

    /msmtp-alternatives
  7. Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft.

    /microsoft-exchange-server-alternatives
  8. sendEmail is a lightweight, command line SMTP email client.

    Open Source

    /sendemail-alternatives
  9. 10

    Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.

    /zimbra-alternatives
  10. A fully fledged, free email server solution, an open source project (GPL v2).

    Open Source

    /iredmail-alternatives
  11. Blat is a small, efficent SMTP command line mailer for Windows.

    /blat-alternatives
  12. mailsend-go is a command line tool to send mail via SMTP protocol, written with golang.

    /mailsend-go-alternatives
  13. 11

    A small Mail Transport Agent (MTA), designed for home and office use. Part of ...

    /dragonfly-mail-agent-alternatives
  14. CMail is a free Windows command line mailer with advanced message formatting options.

    free

    /cmail-alternatives
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