Citadel AlternativesWebMail Providers and other similar apps like Citadel

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. In order to modernize the Citadel platform for the Internet, the Citadel/UX developers added functionality such as shared calendars, instant' and is a webmail provider in the office & productivity category. There are more than 10 alternatives to Citadel for a variety of platforms, including Linux, Web-based, Windows, Self-Hosted and Mac apps. The best Citadel alternative is Kolab Community, which is both free and Open Source. Other great apps like Citadel are Zimbra Collaboration Suite, hMail Server, Microsoft Exchange and SmarterMail Mail Server.

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

More about Citadel
More about Citadel
Citadel alternatives page was last updated Sep 13, 2021
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  1. Kolab Community icon

    Kolab Community

     41 likes
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    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.

    License model

    • Freemium • Open Source

    Application types

    Country of Origin

    • CH flagSwitzerland

    Platforms

    • Linux
    • Online
    • Self-Hosted

    Kolab Community Features

    1.  Real time collaboration
    2.  Video Conferencing
    3.  Contacts
    4.  Voice Chat
    5.  CardDAV Support
    6.  IMAP Support
    7.  CalDAV Support
    8.  WebDAV Support

    Kolab Community VS Citadel

     

    • Kolab Community is the most popular Web-based, Linux & Self-Hosted alternative to Citadel.

    • Kolab Community is the most popular Open Source & free alternative to Citadel.

    • Kolab Community is Freemium and Open SourceCitadel is Free and Open Source
  2. Zimbra Collaboration Suite icon

    Zimbra Collaboration Suite

     35 likes
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    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.

    44 Zimbra Collaboration Suite alternatives

    License model

    • Freemium • Open Source

    Application types

    Country of Origin

    • US flagUnited States

    Platforms

    • Linux
    • Online
    • Self-Hosted
    Zimbra Collaboration Suite screenshot 1

    Zimbra Collaboration Suite Features

    1.  Real time collaboration
    2.  ActiveSync
    3. Microsoft Active Directory icon  Active Directory integration

    Zimbra Collaboration Suite VS Citadel

     
  4. hMail Server icon

    hMail Server

     28 likes
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    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.

    23 hMail Server alternatives

    License model

    • Free • Open Source

    Application type

    Platforms

    • Windows
    hMail Server screenshot 1
    Discontinued

    hMail Server is no longer supported by the people who created it and has been discontinued – so use it at your own risk.

    hMail Server Features

    1.  IMAP Support
    2.  POP3 Support
    3.  SMTP Support
    4.  Convert images to PDF

    hMail Server VS Citadel

     

    • hMail Server is the most popular Windows alternative to Citadel.

    • hMail Server is Free and Open SourceCitadel is also Free and Open Source
  5. Microsoft Exchange icon

    Microsoft Exchange

     17 likes
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    Exchange business-class email helps increase user productivity while protecting your data. Get it as a hosted service or run it on your servers.

    43 Microsoft Exchange alternatives

    License model

    Application type

    Country of Origin

    • US flagUnited States

    Platforms

    • Windows
    • Online
    • Self-Hosted
    • Microsoft Office 365
    Microsoft Exchange screenshot 1

    Microsoft Exchange Features

    1.  Real time collaboration

    Microsoft Exchange VS Citadel

     

    • Microsoft Exchange is the most popular commercial alternative to Citadel.

    • Microsoft Exchange is Paid and ProprietaryCitadel is Free and Open Source
  6. SmarterMail Mail Server icon

    SmarterMail Mail Server

     3 likes
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    SmarterMail is the only other email server on the market with native support for MAPI, the protocol that powers Exchange and Outlook. That means anything you can do on Exchange you can do with SmarterMail: no plug-ins and no additional software required.

    License model

    Application types

    Country of Origin

    • US flagUnited States

    Platforms

    • Windows
    • Linux
    • Docker
    Audio and video conferencing for your team. Includes screen sharing, unlimited chat attendees, file sharing with previews, public or private conferences, and much more.

    Properties

    1.  Privacy focused
    2.  Lightweight

    Features

    1.  Email Organizer
    2.  End-to-End Encryption
    3.  Two-factor Authentication
    4.  Mail Filtering
    5.  WYSIWYG Support
    6.  Multiple Account support
    7.  Passkey Support
    8.  Shared Folders
    9.  Real time collaboration
    10.  No Tracking
    11.  Remote Work
    12.  Video Conferencing

    SmarterMail Mail Server VS Citadel

     
  7. OX App Suite icon

    OX App Suite

     15 likes
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    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.

    19 OX App Suite alternatives

    License model

    • Free • Open Source

    Application types

    Country of Origin

    • DE flagGermany
    • European Union flagEU

    Platforms

    • Linux
    • Online
    • Self-Hosted
    • Software as a Service (SaaS)
    OX Portal

    OX App Suite Features

    1.  Real time collaboration
    2.  Cloud Sync
    3.  Calendar Integration
    4.  Personal Information Manager (PIM)
    5.  Group Mail
    6.  WebDAV Support
    7.  WebDAV Sync

    OX App Suite VS Citadel

     

    • OX App Suite is the most popular SaaS alternative to Citadel.

    • OX App Suite is Free and Open SourceCitadel is also Free and Open Source
  9. CrossBox icon

    CrossBox

     1 like
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    Real-time email, chat, audio/video calls & conferences, file-sharing, and contacts app with a modern and intuitive UI.

    License model

    Application types

    Country of Origin

    • BA flagBosnia & Herzegovina

    Platforms

    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Self-Hosted
    View Mailbox (Dark mode)

    CrossBox Features

    1.  File Hosting

    CrossBox VS Citadel

     

    • CrossBox is the most popular Android, iPhone, iPad & Android Tablet alternative to Citadel.

    • CrossBox is Paid and ProprietaryCitadel is Free and Open Source
  10. MDaemon Messaging Server icon

    MDaemon Messaging Server

     16 likes
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    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.

    24 MDaemon Messaging Server alternatives

    License model

    Application types

    Country of Origin

    • GB flagUnited Kingdom

    Platforms

    • Windows
    MDaemon's web-based email

    MDaemon Messaging Server Features

    1.  Encrypted Email
    2. Microsoft Outlook icon  Outlook integration
    3.  IMAP Support
    4. Dropbox icon  Dropbox integration

    MDaemon Messaging Server VS Citadel

     
  11. EGroupware icon

    EGroupware

     8 likes
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    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.

    24 EGroupware alternatives

    License model

    • Freemium • Open Source

    Application types

    Country of Origin

    • DE flagGermany
    • European Union flagEU

    Platforms

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

    EGroupware Features

    1.  Real time collaboration
    2.  Kanban Board
    3.  Document Sharing
    4.  Remote Work
    5.  Web-Based
    6.  CalDAV Support
    7.  RDP
    8.  WebDAV Support
    9.  CardDAV Support
    10.  Calendar Sync

    EGroupware VS Citadel

     
  12. Zarafa icon

    Zarafa

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

    License model

    Application types

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    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."

    Zarafa Features

    1.  Real time collaboration

    Zarafa VS Citadel

     

    • Zarafa is the most popular Mac alternative to Citadel.

    • Zarafa is Paid and ProprietaryCitadel is Free and Open Source
  13. Atmail Email Server icon

    Atmail Email Server

     7 likes
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    Atmail webmail system offers a webmail client, email server platform and mailserver appliance for Linux, Unix and Windows.

    License model

    Application types

    Country of Origin

    • AU flagAustralia

    Platforms

    • Linux
    • Online
    Intuitive Webmail Interface

    Atmail Email Server Features

    1.  Group Mail

    Atmail Email Server VS Citadel

     
  14. Expanding Communication icon

    Expanding Communication

     5 likes
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    Turnkey Solutions for the Enterprise Cloud

    Installation, Configuration, and Management tools for enterprise email, collaboration, messaging, video conferencing, file sharing, and file transfers.

    License model

    Application types

    Platforms

    • Linux
    Expanding Communication screenshot 1

    Expanding Communication Features

    1.  Cloud Sync
    2.  Contacts
    3.  CalDAV Support
    4.  Cloud based
    5.  Video Conferencing
    6.  CardDAV Support

    Expanding Communication VS Citadel

     
12 of 18 Citadel alternatives