Citadel vs Openmeetings
A side-by-side comparison of two self-hosted groupware options — licensing, setup difficulty, resource needs, and what each one replaces.
Not the right match-up?
Citadel
All-in-one groupware, mail and collaboration server
VS
Openmeetings
Video conferencing, instant messaging, whiteboard, collaborative
| Feature | Citadel | Openmeetings |
|---|---|---|
| Category | Groupware | Groupware |
| License | GPL-3.0 | Apache-2.0 |
| Language | C | Java |
| Setup difficulty | Medium | Medium |
| Min. RAM | 512 MB | 512 MB |
| Deployment | bare-metal, source | bare-metal |
| GitHub stars | ★ 100 | ★ 686 |
| First released | 1987 | 2025 |
| Replaces | Microsoft Exchange, Microsoft 365 | — |
Why pick each one
Choose Openmeetings if…
- Released under the Apache-2.0 license
- Written in Java
- Lightweight — runs in 512 MB RAM
Frequently asked questions
Is Citadel or Openmeetings better?
Neither is universally better. Openmeetings has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.
Are Citadel and Openmeetings free and open-source?
Yes. Citadel is licensed under GPL-3.0 and Openmeetings under Apache-2.0. Both can be self-hosted at no software cost.
Can I run Citadel and Openmeetings with Docker?
Citadel: check the project docs for container support. Openmeetings: check the project docs for container support.