SHSelfHostIndex

Stalwart Mail Server vs OpenSMTPD

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 OP OpenSMTPD Secure and simple SMTP server from OpenBSD
FeatureStalwart Mail ServerOpenSMTPD
CategoryMail ServersMail Servers
LicenseAGPL-3.0ISC
LanguageRustC
Setup difficultyMediumMedium
Min. RAM512 MB32 MB
Deploymentdocker, binary, bare-metalbare-metal, source
GitHub stars★ 14,059★ 579
First released20202013
ReplacesMicrosoft Exchange, Google WorkspaceSendmail, Postfix

Why pick each one

Choose Stalwart Mail Server if…

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

Choose OpenSMTPD if…

  • Clean concise config
  • Strong security record
OpenSMTPD details

Frequently asked questions

Is Stalwart Mail Server or OpenSMTPD better?

Neither is universally better. Stalwart Mail Server has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.

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

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

Can I run Stalwart Mail Server and OpenSMTPD with Docker?

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

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