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Citadel Alternatives

Citadel is described as 'Is a collaboration suite (messaging and groupware). It is designed to run on open source operating systems such as Linux or BSD' and is a webmail provider in the office & productivity category. There are more than 10 alternatives to Citadel for a variety of platforms, including Online / Web-based, Windows, Linux, Self-Hosted solutions and Mac. The best alternative is Zimbra Collaboration Suite, which is both free and Open Source. Other great apps like Citadel are Kolab Community, hMail Server, OX App Suite and Microsoft Exchange Server.

Citadel alternatives are mainly Mail Servers but may also be WebMail Providers or Calendar Apps. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of Citadel.
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Citadel
  6
  • FreeOpen Source
  • Linux
  • Online

Is a collaboration suite (messaging and groupware). It is designed to run on open source operating systems such as Linux...

Learn more about Citadel

  1. Zimbra Collaboration is an open, secure collaboration tool for email, calendaring, tasks and more. With the most innovative web application available today, Zimbra boosts the productivity of users on any desktop and dramatically reduces TCO compared to legacy platform vendors.

    Screenshot
  2. Kolab Community icon

    Kolab Community

    • FreemiumOpen Source
    • Linux
    • Online
    • Self-Hosted

    Kolab is entirely Free and Open Source Software (a.k.a. FOSS), and uses Open Standards. We’ll get to why this is important to us, and hope that it is important to you thereafter.

    No screenshots yet


  3. hMailServer is a free e-mail server for Microsoft Windows. Its used by Internet service providers, companies, governments, schools and enthusiasts in all parts of the world.

    Screenshot
  4. OX App Suite icon

    OX App Suite

    • FreeOpen Source
    • Linux
    • Online
    • Self-Hosted
    • Software as a Service (SaaS)

    The OX App Suite by Open-Xchange is web-based platform offering a suite of apps like an email client, calendar, contacts magement, cloud storage with synchronization and productivity apps for word processing, spreadsheets and presentations.

    OX Portal
  5. Microsoft Exchange Server icon

    Microsoft Exchange Server

    • Windows
    • Online

    Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft. It is part of the Microsoft Servers line of server products and is widely used by enterprises using Microsoft infrastructure solutions.

    Screenshot


  6. Low cost, easy to use Email Server software for virtual, on-premise, or hosted deployments for companies that want control of their email. Integrated web-mail with doc sharing, Drop Box integration, client and server side encryption.

    MDaemon's web-based email
  7. iMail icon

    iMail

    • Windows
    • Self-Hosted

    Fast, safe, heavy mail solution. Web-client access, LAN or WAN self-hosted server, maintenance-free design. No Windows server and database server required, unlimited mail accounts, storage, attachment size, custom logo. Free for commercial use.

    iMail Server LAN Client.
  8. Sanwhole Exchange icon

    Sanwhole Exchange

    • Windows

    Sanwhole Exchange is a server running iMail, iPress and iStore services. iMail is an enterprise-class email server does Microsoft Exchange and Gmail work. iPress sets blog, forums and tickets in one. iStore is an online store.

    iMail
  9. Online Collaboration with Chat and Online Office. Is developed as open source software in Germany, offered as free community version and as commercial version. Operation as self-hosted or as SaaS from the computer centre.

    EGroupware on the desktop
   ---   
EGroupware offers with the modules

- E-mail
- Calendar
- Address book
- InfoLog (tasks, notes, ...)
- File manager
- Ticket system
- Project Manager
- Timesheet

- Collabora Online Office
- Rocket.Chat

an entire office in the browser.
  10. Zarafa icon

    Zarafa

    • Mac
    • Windows
    • Linux
    • Online

    Open Source Collaboration, providing integration with your existing Linux mailserver, native mobile phone support, Outlook "Look & Feel" webaccess and stable Outlook sharing (100% MAPI).

    Discontinued

    "Last year we released the announcement that Zarafa customers could transition to Kopano. We also announced that Zarafa would not be maintained beyond May 1st, 2017. Most ZCP customers have moved to a Kopano subscription now."

    No screenshots yet
Showing 10 of 17 alternatives