SHSelfHostIndex

Citadel vs Kopano Groupware Core

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?
CI Citadel All-in-one groupware, mail and collaboration server VS KO Kopano Groupware Core Open-source collaboration platform with Outlook support
FeatureCitadelKopano Groupware Core
CategoryGroupwareGroupware
LicenseGPL-3.0AGPL-3.0
LanguageCC++
Setup difficultyMediumHard
Min. RAM512 MB2,048 MB
Deploymentbare-metal, sourcedocker, bare-metal
GitHub stars★ 100★ 60
First released19872016
ReplacesMicrosoft Exchange, Microsoft 365Microsoft Exchange

Why pick each one

Choose Citadel if…

  • Single-package setup
  • Low resource needs
Citadel details

Choose Kopano Groupware Core if…

  • Released under the AGPL-3.0 license
  • First-class Docker support for quick deployment
  • Written in C++
Kopano Groupware Core details

Frequently asked questions

Is Citadel or Kopano Groupware Core better?

Citadel is the stronger all-round pick: it has both the larger community and the simpler medium setup. Consider Kopano Groupware Core if its specific feature set fits your needs better.

Are Citadel and Kopano Groupware Core free and open-source?

Yes. Citadel is licensed under GPL-3.0 and Kopano Groupware Core under AGPL-3.0. Both can be self-hosted at no software cost.

Can I run Citadel and Kopano Groupware Core with Docker?

Citadel: check the project docs for container support. Kopano Groupware Core: yes.

Related comparisons