Compare software

OpenSMTPDchasquid
Free

Free and open source under the ISC license.

 Free

Free and open source under the Apache 2.0 licence.

Linux, Self-hosted, Command line Linux, Self-hosted
  • Part of the OpenBSD project
  • Simpler than many other SMTP servers
  • Secure defaults that prevent open relays
  • Virtual domains with per-domain users and aliases
  • A mail server, not a client for reading email
  • Needs other components for a complete mail setup
  • Aimed at individuals and small groups rather than large deployments
  • Needs Dovecot or similar for mailbox access
Downloadable app, Self-hosted Downloadable app, Self-hosted
Open source Open source
License: ISC License: Apache-2.0
No account needed No account needed
Not stated if it works offline Not stated if it works offline

Checked September 24, 2026

Checked October 2, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.