This page is mainly to compare all active and mature Open Source (thus self-hostable) webmail solutions that you can install and manage email from any server with standard email protocols (IMAP, SMTP, JMAP). The assumption is that you already have at least one mail server (and often more than one) and you just want to install a webmail, and perhaps replace a desktop email solution like Thunderbird.
Here are the main Open Source standalone webmail options:
Special cases:
Some related solutions are added because they have a close connection with the solutions above
Not included (yet), and why?
| Roundcube | Kolab | SnappyMail (RainLoop fork) | Nextcloud | Cypht | Tiki Wiki CMS Groupware | Virtualmin | |
| Type | Webmail in PHP | Full mail server back-end and front-end | Webmail in PHP and Node.JS | Multi-feature system which offers plugins/modules, and some of those do mail client | Pluggable Webmail in PHP with aggregator mindset | Multi-feature system which offers all the functionality in one app (bundles Cypht Webmail) | Admin panel for shared hosting (which includes mail accounts and webmail) |
| Mail server | None | Yes | None | None | None | None | Dovecot |
| Webmail client | Yes | uses Roundcube. | Yes | Nextcloud mail | Yes | Yes, uses Cypht | Usermin Webmail. |
| How does it deal with mail accounts? | Only 1 external account at a time | Only own accounts | Multiple external accounts | ? | Multiple external accounts | Multiple external accounts (via Cypht) | Only own accounts |
| Calendar | ? | Yes | ? | Nextcloud calendar | super basic | Tiki Calendar | No |
| Contacts | Yes | uses Roundcube | Yes | Yes? | Yes | Tiki Contacts | Yes |
| Manage Sieve | plugin? | Yes? | ? | ? | Yes | Via Cypht | No (uses Procmail instead) |
| Calendar invitations by email | ? | Yes | ? | Yes? | No | Yes | No |
| Uses Bootstrap | Yes | yes, via Roundcube | Yes | No | No | Yes | Yes |
| Mail: Search throughout all folders | Yes | Yes, via Roundcube | Yes | ? | Missing | Missing (via Cypht) | ? |
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