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Simple NixOS MailserverPostfix
Free

Free and open source under the GPL-3.0 licence.

 Free

Free and open source.

Linux, Self-hosted macOS, Linux, Self-hosted
  • Whole mail server defined declaratively in NixOS configuration
  • Releases track each NixOS release
  • Security-focused design
  • Runs on many Unix-like systems
  • Only works on NixOS
  • Running a mail server still requires DNS and deliverability knowledge
  • Transfer agent only; needs a separate IMAP server for mailboxes
  • Configuration requires mail server knowledge
Self-hosted Self-hosted
Open source Open source
License: GPL-3.0 License not stated
Not stated if an account is needed No account needed
Not stated if it works offline Not stated if it works offline

Checked October 2, 2026

Checked September 24, 2026

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