Stalwart Mail Server vs fdm

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?
FeatureStalwart Mail Serverfdm
CategoryMail ServersMail Servers
LicenseAGPL-3.0ISC
LanguageRustC
Setup difficultyMediumMedium
Min. RAM512 MB32 MB
Deploymentdocker, binary, bare-metalbinary, source
GitHub stars★ 14,059★ 283
First released20202006
ReplacesMicrosoft Exchange, Google Workspacefetchmail, procmail

Why pick each one

Choose Stalwart Mail Server if…

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

Choose fdm if…

  • Released under the ISC license
  • Written in C
  • Tiny footprint — runs in 32 MB RAM
fdm details

Frequently asked questions

Is Stalwart Mail Server or fdm 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 fdm free and open-source?

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

Can I run Stalwart Mail Server and fdm with Docker?

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

Related comparisons