Mailu vs RainLoop
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?
Mailu
Simple yet full-featured Docker mail server
VS
RainLoop
Simple, modern and fast web-based email client
| Feature | Mailu | RainLoop |
|---|---|---|
| Category | Mail Servers | Mail Servers |
| License | MIT | AGPL-3.0 |
| Language | Python | PHP |
| Setup difficulty | Medium | Easy |
| Min. RAM | 2,048 MB | 128 MB |
| Deployment | docker, kubernetes | docker, bare-metal, source |
| GitHub stars | ★ 7,443 | ★ 4,120 |
| First released | 2016 | 2013 |
| Replaces | Google Workspace, Microsoft 365 | Gmail, Outlook Web |
Why pick each one
Choose RainLoop if…
- Released under the AGPL-3.0 license
- Easy to set up — beginner-friendly
- First-class Docker support for quick deployment
- Active community (4.1k GitHub stars)
Frequently asked questions
Is Mailu or RainLoop better?
Neither is universally better. Mailu has the larger community, while RainLoop is simpler to set up (easy difficulty). Choose based on the comparison table above and your own setup.
Are Mailu and RainLoop free and open-source?
Yes. Mailu is licensed under MIT and RainLoop under AGPL-3.0. Both can be self-hosted at no software cost.
Can I run Mailu and RainLoop with Docker?
Mailu: yes. RainLoop: yes.