Citadel vs Group-Office
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
Group-Office
Web-based groupware and CRM with email and calendar
| Feature | Citadel | Group-Office |
|---|---|---|
| Category | Groupware | Groupware |
| License | GPL-3.0 | AGPL-3.0 |
| Language | C | PHP |
| Setup difficulty | Medium | Medium |
| Min. RAM | 512 MB | 1,024 MB |
| Deployment | bare-metal, source | docker, bare-metal |
| GitHub stars | ★ 100 | ★ 275 |
| First released | 1987 | 2003 |
| Replaces | Microsoft Exchange, Microsoft 365 | Microsoft 365, Google Workspace |
Why pick each one
Choose Group-Office if…
- Released under the AGPL-3.0 license
- First-class Docker support for quick deployment
- Written in PHP
Frequently asked questions
Is Citadel or Group-Office better?
Neither is universally better. Group-Office has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.
Are Citadel and Group-Office free and open-source?
Yes. Citadel is licensed under GPL-3.0 and Group-Office under AGPL-3.0. Both can be self-hosted at no software cost.
Can I run Citadel and Group-Office with Docker?
Citadel: check the project docs for container support. Group-Office: yes.