SHSelfHostIndex

Stalwart Mail Server vs Nullmailer

A side-by-side comparison of two self-hosted mail servers options — licensing, setup difficulty, resource needs, and what each one replaces.

Not the right match-up?
ST Stalwart Mail Server Modern all-in-one mail server in a single binary VS NU Nullmailer Simple relay-only mail transfer agent
FeatureStalwart Mail ServerNullmailer
CategoryMail ServersMail Servers
LicenseAGPL-3.0GPL-2.0
LanguageRustC++
Setup difficultyMediumEasy
Min. RAM512 MB16 MB
Deploymentdocker, binary, bare-metalbare-metal, source
GitHub stars★ 14,059★ 199
First released20202000
ReplacesMicrosoft Exchange, Google WorkspaceSendmail

Why pick each one

Choose Stalwart Mail Server if…

  • Single modern binary
  • Strong security defaults
Stalwart Mail Server details

Choose Nullmailer if…

  • Extremely lightweight
  • Simple configuration
Nullmailer details

Frequently asked questions

Is Stalwart Mail Server or Nullmailer better?

Neither is universally better. Stalwart Mail Server has the larger community, while Nullmailer is simpler to set up (easy difficulty). Choose based on the comparison table above and your own setup.

Are Stalwart Mail Server and Nullmailer free and open-source?

Yes. Stalwart Mail Server is licensed under AGPL-3.0 and Nullmailer under GPL-2.0. Both can be self-hosted at no software cost.

Can I run Stalwart Mail Server and Nullmailer with Docker?

Stalwart Mail Server: yes. Nullmailer: check the project docs for container support.

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