Mailspring 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?
| Feature | Mailspring | Sup |
|---|---|---|
| Category | Mail Servers | Mail Servers |
| License | GPL-3.0 | GPL-2.0 |
| Language | JavaScript | Ruby |
| Setup difficulty | Easy | Medium |
| Min. RAM | 512 MB | 128 MB |
| Deployment | binary, source | binary, source |
| GitHub stars | ★ 17,730 | ★ 970 |
| First released | 2017 | 2007 |
| Replaces | Outlook, Apple Mail | Mutt |
Why pick each one
Choose Mailspring if…
- Released under the GPL-3.0 license
- Easy to set up — beginner-friendly
- Mature project with 17.7k GitHub stars
- Written in JavaScript
Choose Sup if…
- Released under the GPL-2.0 license
- Written in Ruby
- Tiny footprint — runs in 128 MB RAM
Frequently asked questions
Is Mailspring or Sup better?
Mailspring is the stronger all-round pick: it has both the larger community and the simpler easy setup. Consider Sup if its specific feature set fits your needs better.
Are Mailspring and Sup free and open-source?
Yes. Mailspring is licensed under GPL-3.0 and Sup under GPL-2.0. Both can be self-hosted at no software cost.
Can I run Mailspring and Sup with Docker?
Mailspring: check the project docs for container support. Sup: check the project docs for container support.