Stalwart Mail Server vs Sup
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?
Stalwart Mail Server
Modern all-in-one mail server in a single binary
VS
Sup
Console-based threaded email client
| Feature | Stalwart Mail Server | Sup |
|---|---|---|
| Category | Mail Servers | Mail Servers |
| License | AGPL-3.0 | GPL-2.0 |
| Language | Rust | Ruby |
| Setup difficulty | Medium | Medium |
| Min. RAM | 512 MB | 128 MB |
| Deployment | docker, binary, bare-metal | binary, source |
| GitHub stars | ★ 14,059 | ★ 970 |
| First released | 2020 | 2007 |
| Replaces | Microsoft Exchange, Google Workspace | Mutt |
Why pick each one
Choose Stalwart Mail Server if…
- Single modern binary
- Strong security defaults
Choose Sup if…
- Released under the GPL-2.0 license
- Written in Ruby
- Tiny footprint — runs in 128 MB RAM
Frequently asked questions
Is Stalwart Mail Server or Sup 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 Sup free and open-source?
Yes. Stalwart Mail Server is licensed under AGPL-3.0 and Sup under GPL-2.0. Both can be self-hosted at no software cost.
Can I run Stalwart Mail Server and Sup with Docker?
Stalwart Mail Server: yes. Sup: check the project docs for container support.