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Citadel

Meet the Citadel System. Easy to install. Easy to use. 100% open source. No compromises.

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Citadel is an open source groupware and content management system that brings email, collaboration, and publishing tools into a single platform. It is designed to be installed and running within minutes, either on self-hosted hardware or in the cloud, and organizes its features around a rooms-based architecture that provides a consistent structure across its different modules.

The system includes email, calendar, and contacts, alongside forums, mailing lists, and instant messaging. It also provides wiki, blog, and RSS aggregation tools, with multi-domain support managed through a web interface. Citadel is written in C and distributed under the GNU General Public License, with the freely available download representing the complete software rather than a limited edition.

Citadel is suited to organizations and individuals who want to self-host a unified communication and content platform on their own infrastructure or in the cloud. The software is provided as free software under the GNU General Public License, with no separate editions or paid tiers described.

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