Citadel vs EGroupware
A side-by-side comparison of two self-hosted groupware options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | Citadel | EGroupware |
|---|---|---|
| Deploy effort | Read-the-docs project | Under-an-hour setup |
| Category | Groupware | Groupware |
| License | GPL-3.0 | GPL-2.0 |
| Language | C | PHP |
| Setup difficulty | Medium | Medium |
| Min. RAM | 512 MB | 1,024 MB |
| Deployment | bare-metal, source | docker, bare-metal |
| GitHub stars | ★ 100 | ★ 297 |
| First released | 1987 | 2003 |
| Replaces | Microsoft Exchange, Microsoft 365 | Microsoft 365, Google Workspace |
What are Citadel and EGroupware?
Citadel
Citadel is a mature, all-in-one collaboration suite that integrates email, calendaring, address books, instant messaging, and bulletin boards. It is designed for easy installation and minimal maintenance.
- Integrated mail and calendar
- Built-in groupware web client
- Instant messaging and forums
- Easy installer
EGroupware
EGroupware is a browser-based groupware suite that includes calendar, address book, email, project management, and file sharing. It supports CalDAV, CardDAV, and ActiveSync for client synchronization.
- Integrated calendar, mail and contacts
- Project management and timesheets
- CalDAV/CardDAV and ActiveSync
- Video conferencing module
Citadel vs EGroupware: key differences
Citadel is written in C, while EGroupware is built with PHP. Licensing differs — GPL-3.0 for Citadel versus GPL-2.0 for EGroupware. Citadel is the lighter option, starting around 512 MB of RAM against 1,024 MB for EGroupware. Citadel is the more established project (first released 1987), while EGroupware arrived in 2003. EGroupware has the considerably larger community, at 297 GitHub stars versus 100. EGroupware lists first-class Docker deployment; Citadel does not.
Why pick each one
Choose Citadel if…
- Single-package setup
- Low resource needs
Watch out for
- Niche project
- Old-fashioned UI
Choose EGroupware if…
- Broad feature set
- Long-established project
Watch out for
- Interface feels dated
- Many modules to configure
Frequently asked questions
Is Citadel or EGroupware better?
Neither is universally better. EGroupware has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.
Are Citadel and EGroupware free and open-source?
Yes. Citadel is licensed under GPL-3.0 and EGroupware under GPL-2.0. Both can be self-hosted at no software cost.
Can I run Citadel and EGroupware with Docker?
Citadel: check the project docs for container support. EGroupware: yes.
Which is lighter on resources, Citadel or EGroupware?
Citadel has the smaller minimum footprint at 512 MB of RAM, compared to about 1,024 MB for EGroupware. Real-world usage depends on library size, user count, and enabled features.