Citadel

Self-Hosted

Open-source groupware suite for secure collaboration and communication

Overview

Citadel is an all-in-one open-source groupware platform that integrates email, calendar, contacts, task management, file sharing, instant messaging, and discussion forums. Built for self-hosting, it offers easy deployment via Docker or traditional server setups, making it suitable for small teams to enterprises. It prioritizes data privacy and control, letting users manage sensitive information on their own infrastructure without third-party reliance. With a focus on simplicity and robustness, Citadel streamlines collaboration while keeping operations lightweight and cost-effective.

Self-Hosting Resources

Find Official Image on Docker Hub View Source & Docs

Below is a reference structure for docker-compose.yml. ⚠️ Do NOT run blindly. Replace placeholders with official values.

docker-compose.template.yml TEMPLATE


version: '3'
services:
  citadel:
    image: <OFFICIAL_IMAGE_NAME>:latest
    container_name: citadel
    ports:
      - "8080:<APP_INTERNAL_PORT>"
    volumes:
      - ./data:/app/data
    restart: unless-stopped

Key Features

Unified suite: email, calendar, contacts & tasks
File sharing and instant messaging
Docker-powered deployment for quick setup

Frequently Asked Questions

? Is Citadel hard to install?

Citadel offers simple deployment options like Docker containers, which reduce setup to a few commands. Traditional installations are also well-documented, making it accessible for users with basic server admin knowledge.

? Is it a good alternative to Microsoft 365?

Yes—Citadel provides core groupware features (email, calendar, etc.) with full data control via self-hosting, making it ideal for teams prioritizing privacy over SaaS integrations.

? Is it completely free?

Citadel is open-source under the GNU GPL license. It’s 100% free to use, modify, and self-host without subscription fees or hidden costs.

Top Alternatives

Microsoft 365 Search Google

Google Workspace Search Google

Tool Info

Pricing Open Source

Category Groupware

Platform Self-Hosted

Pros

⊕ Privacy-focused self-hosting
⊕ All-in-one collaboration tools
⊕ Lightweight resource footprint

Cons

⊖ Outdated user interface
⊖ Limited third-party app integrations
⊖ Steeper learning curve for advanced configurations