OpenSourceProjects

Open Source Citadel Alternatives

Discover 4 open source alternatives to Citadel. All free, community-driven, and actively maintained.

What is Citadel?

Citadel is a groupware and bulletin board system software for hosting online communities and messaging.

mailcow-dockerized

mailcow-dockerized

mailcow: dockerized - 🐮 + 🐋 = 💕

stalwart

stalwart

All-in-one Mail & Collaboration server. Secure, scalable and fluent in every protocol (IMAP, JMAP, SMTP, CalDAV, CardDAV, WebDAV).

Mailu

Mailu

Insular email distribution - mail server as Docker images

sogo

sogo

SOGo is a very fast and scalable modern collaboration suite (groupware). It offers calendaring, address book management, and a full-featured Webmail client along with resource sharing and permission handling. It also makes use of documented standards (IMAP, CalDAV, CardDAV, etc.) and thereby provides native connectivity (without plugins) to many clients such as Microsoft Outlook, Apple iCal, the iPhone, Mozilla Lightning, and a plethora of mobile devices.