Mail-in-a-Box vs isync
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
isync
IMAP and Maildir mailbox synchronizer
| Feature | Mail-in-a-Box | isync |
|---|---|---|
| Category | Mail Servers | Mail Servers |
| License | CC0-1.0 | GPL-2.0 |
| 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 | ★ 400 |
| First released | 2014 | 2000 |
| Replaces | Google Workspace, Microsoft 365 | Outlook offline mode |
Why pick each one
Choose isync if…
- Released under the GPL-2.0 license
- Written in C
- Tiny footprint — runs in 32 MB RAM
Frequently asked questions
Is Mail-in-a-Box or isync better?
Mail-in-a-Box is the stronger all-round pick: it has both the larger community and the simpler easy setup. Consider isync if its specific feature set fits your needs better.
Are Mail-in-a-Box and isync free and open-source?
Yes. Mail-in-a-Box is licensed under CC0-1.0 and isync under GPL-2.0. Both can be self-hosted at no software cost.
Can I run Mail-in-a-Box and isync with Docker?
Mail-in-a-Box: check the project docs for container support. isync: check the project docs for container support.