Citadel alternatives

Nearest on its board

1. 10
   M

   Mailumailu.io

   The project aims to provide an easily set up and maintained full-featured mail server without proprietary software or unrelated groupware features.

   6.2 APIOpenFree Free tier
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2. 12
   E

   Eximexim.org

   Exim is a mail transfer agent for hosts running Unix or Unix-like operating systems.

   6.2 APIOpenFree Free tier
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3. 9
   I

   iRedMailiredmail.org

   iRedMail is open-source software for deploying a full-featured mail server.

   6.2 APIOpenFree Free tier · from $10/yr
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4. 13
   MI

   Mail-in-a-Boxmailinabox.email

   Mail-in-a-Box turns a fresh cloud computer into a mail server that lets users run their own email service.

   6.1 APIOpenFree Free tier
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5. 8
   SM

   Stalwart Mail Serverstalwart.email

   Stalwart is an open-source mail and collaboration server for email, calendars, contacts, and shared files.

   6.3 APIOpenFree Free tier · from $1.09/yr
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6. 14
   P

   Postfixpostfix.org

   Postfix aims to be fast, easy to administer, and secure.

   6.1 APIOpenFree Free tier
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7. 7
   S

   SmarterMailsmartertools.com

   SmarterMail is an email, groupware, and collaboration server positioned as an alternative to Microsoft Exchange.

   6.3 APIOpenFree Free tier · from $500/yr
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8. 15
   M

   Modoboamodoboa.org

   Modoboa is an open-source platform for installing and managing a self-hosted email server.

   6.1 APIOpenFree Free tier · from €139/yr
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9. 6
   M

   MailEnablemailenable.com

   MailEnable is a hosted messaging software suite for the Microsoft platform.

   6.3 APIOpenFree Free tier · $395 one-time
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10. 16
    H

    hMailServerhmailserver.com

    hMailServer is a self-hosted mail server that supports SMTP, IMAP and POP3.

    6.0 APIOpenFree Free tier
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11. 5
    K

    Kolabkolab.org

    Kolab is a free and open-source communication and collaboration solution that can be run on your own infrastructure.

    6.3 APIOpenFree Free tier
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12. 17
    PI

    poste.ioposte.io

    Poste.io is a self-hosted email server with web administration, webmail, spam protection, and mail server components in one Docker container.

    6.0 APIOpenFree Free tier · from $349/yr
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13. 4
    Q

    qmailcr.yp.to

    qmail is a secure, reliable, efficient message transfer agent for typical Internet-connected UNIX hosts.

    6.3 APIOpenFree Free tier
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14. 18
    ZC

    Zimbra Collaborationzimbra.com

    Zimbra is an enterprise email and collaboration suite with email, calendar, contacts, tasks, and file sharing.

    6.0 APIOpenFree Free tier
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15. 3
    CM

    Courier Mail Servercourier-mta.org

    Courier is an integrated mail and groupware server providing ESMTP, IMAP, POP3, webmail, and mailing list services.

    6.3 APIOpenFree Free tier
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16. 19
    CI

    Cyrus IMAPcyrusimap.org

    Cyrus IMAP is an email, contacts, and calendar server.

    5.9 APIOpenFree Free tier
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17. 2
    M

    mailcowmailcow.email

    mailcow: dockerized is an open-source groupware and email suite based on Docker.

    6.4 APIOpenFree Free tier · from €8.90/mo
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18. 20
    I

    IceWarpicewarp.com

    IceWarp is an all-in-one collaboration platform combining email, messaging, video conferencing, file sharing, and real-time document collaboration in one…

    5.9 APIOpenFree From $1.35/mo
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19. 1
    A

    Axigenaxigen.com

    Axigen is an all-in-one email, calendaring, and collaboration platform for organizations from small businesses to large service providers.

    6.4 APIOpenFree Free tier
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20. 21
    MM

    Maddy Mail Servermaddy.email

    Maddy implements the functionality to send and receive email over SMTP and store messages with IMAP access.

    5.9 APIOpenFree Free tier
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