Mail-in-a-Box vs Mailu
A side-by-side comparison of two self-hosted mail servers options — licensing, setup difficulty, resource needs, and what each one replaces.
Mail-in-a-Box
Turn a fresh server into a working mail server
VS
Mailu
Simple yet full-featured Docker mail server
| Feature | Mail-in-a-Box | Mailu |
|---|---|---|
| Deploy effort | ≈5-minute setup | Under-an-hour setup |
| Health score | 94 · Excellent | 91 · Excellent |
| Category | Mail Servers | Mail Servers |
| License | CC0-1.0 | MIT |
| Language | Python | Python |
| Setup difficulty | Easy | Medium |
| Min. RAM | 1,024 MB | 2,048 MB |
| Deployment | bare-metal, one-click | docker, kubernetes |
| GitHub stars | ★ 15,418 | ★ 7,524 |
| First released | 2014 | 2016 |
| Replaces | Google Workspace, Microsoft 365 | Google Workspace, Microsoft 365 |
What are Mail-in-a-Box and Mailu?
Mail-in-a-Box
Mail-in-a-Box is an easy-to-deploy bundle that turns a clean Ubuntu server into a complete mail and web server. It automates DNS, webmail, contacts, calendar, and antispam setup.
- One-command full mail setup
- Automatic DNS and TLS
- Roundcube webmail and Nextcloud contacts
- Built-in admin dashboard
Mailu
Mailu is a free mail server distributed as a set of Docker images, providing a complete stack with antispam, webmail, and admin interface. It aims to be simpler and lighter than other mail suites.
- Composable Docker images
- Built-in antispam and antivirus
- Roundcube and SnappyMail webmail
- Admin UI and REST API
Mail-in-a-Box vs Mailu: key differences
Both projects are written in Python. Licensing differs — CC0-1.0 for Mail-in-a-Box versus MIT for Mailu. Mail-in-a-Box is the lighter option, starting around 1,024 MB of RAM against 2,048 MB for Mailu. Mail-in-a-Box is the more established project (first released 2014), while Mailu arrived in 2016. Mail-in-a-Box has the considerably larger community, at 15,418 GitHub stars versus 7,524. Mailu lists first-class Docker deployment; Mail-in-a-Box does not.
Why pick each one
Choose Mail-in-a-Box if…
- Very beginner-friendly
- Opinionated, complete stack
Watch out for
- Limited customization
- Dedicated server required
Choose Mailu if…
- Lighter than mailcow
- Kubernetes support
Watch out for
- Fewer features than larger suites
- Manual DNS configuration
Frequently asked questions
Is Mail-in-a-Box or Mailu better?
Mail-in-a-Box is the stronger all-round pick: it has both the larger community and the simpler easy setup. Consider Mailu if its specific feature set fits your needs better.
Are Mail-in-a-Box and Mailu free and open-source?
Yes. Mail-in-a-Box is licensed under CC0-1.0 and Mailu under MIT. Both can be self-hosted at no software cost.
Can I run Mail-in-a-Box and Mailu with Docker?
Mail-in-a-Box: check the project docs for container support. Mailu: yes.
Which is lighter on resources, Mail-in-a-Box or Mailu?
Mail-in-a-Box has the smaller minimum footprint at 1,024 MB of RAM, compared to about 2,048 MB for Mailu. Real-world usage depends on library size, user count, and enabled features.