Mail-in-a-Box 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?
Mail-in-a-Box
Turn a fresh server into a working mail server
VS
fdm
Fetch and filter mail with a single configuration
| Feature | Mail-in-a-Box | fdm |
|---|---|---|
| Category | Mail Servers | Mail Servers |
| License | CC0-1.0 | ISC |
| Language | Python | C |
| Setup difficulty | Easy | Medium |
| Min. RAM | 1,024 MB | 32 MB |
| Deployment | bare-metal, one-click | binary, source |
| GitHub stars | ★ 15,385 | ★ 283 |
| First released | 2014 | 2006 |
| Replaces | Google Workspace, Microsoft 365 | fetchmail, procmail |
Why pick each one
Choose fdm if…
- Released under the ISC license
- Written in C
- Tiny footprint — runs in 32 MB RAM
Frequently asked questions
Is Mail-in-a-Box or fdm better?
Mail-in-a-Box is the stronger all-round pick: it has both the larger community and the simpler easy setup. Consider fdm if its specific feature set fits your needs better.
Are Mail-in-a-Box and fdm free and open-source?
Yes. Mail-in-a-Box is licensed under CC0-1.0 and fdm under ISC. Both can be self-hosted at no software cost.
Can I run Mail-in-a-Box and fdm with Docker?
Mail-in-a-Box: check the project docs for container support. fdm: check the project docs for container support.