WikiSuite | Webmail and groupware comparison

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.

This page is a wiki page, so please join us to make it better.

Here are the main active and mature Open Source standalone webmail options:

Roundcube
SnappyMail (RainLoop fork)
Cypht

Special cases:

Nextcloud Mail requires Nextcloud (And in Nextcloud, you can pick other options like the module for SnappyMail). See also WikiSuite vs Nextcloud
Tiki Wiki CMS Groupware (which bundles Cypht)

Some related solutions are added because they have a close connection with one of the solutions above

Kolab is added because it uses Roundcube and has massively contributed to it in the last few years..
Virtualmin is added because it is the mail stack of WikiSuite (And Tiki is also a WikiSuite component)

	Roundcube	Kolab	SnappyMail (RainLoop fork)	Nextcloud	Cypht	Tiki Wiki CMS Groupware	Virtualmin
Type	Webmail in PHP	Full mail server stack (server and webmail)	Webmail in PHP and Node.JS	Multi-feature system which offers plugins/modules, and some of those are webmail clients	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 its own webmail (You can also install Cypht, Roundcube, etc.)
Mail server	NoneIt's an email client, and you can connect to any mail server via standard protocols (IMAP, etc.)	Cyrus IMAP	NoneIt's an email client, and you can connect to any mail server via standard protocols (IMAP, etc.)	NoneIt's an email client, and you can connect to any mail server via standard protocols (IMAP, etc.)	NoneIt's an email client, and you can connect to any mail server via standard protocols (IMAP, etc.)	NoneIt's an email client, and you can connect to any mail server via standard protocols (IMAP, etc.)	Dovecot
License	GPLv3+ with exceptions for skins and plugins	Various components use various Open Source licenses	AGPLv3	AGPLv3	LGPL v2.1	LGPL v2.1	GPL
Available via Packagist.org	No	No	No	No	Yes	No	No
Available via Docker	yes	This image does not provide persistence, and is intended for testing and demo purposes	?	Yes	Yes	Yes	No
Uses Bootstrap	Yes	yes, via Roundcube	Yes?	No	Yes	Yes	Yes
External authentication	?	?	?	Yes, via Nextcloud (social logins, oidc, ldap, others)	API, LDAP and others	LDAP (Active Directory), OpenID Connect, SAML, Hybridauth Social Sign On Library, CAS, Shibboleth, etc.	?
Webmail client	Yes	Yes, via Roundcube	Yes	Nextcloud mail	Yes	Yes, via Cypht	Usermin Webmail.
How does it deal with mail accounts?	Only 1 external account at a time	Only own accounts?	Multiple external accounts but messages are not in a unified view	Multiple external accounts in a unified view	Multiple external accounts in one view	Multiple external accounts (via Cypht)	Only own accounts?
Possible to copy/move an email between IMAP accounts?	No	No	No	?	Yes	Yes, via Cypht	?
Manage Sieve	via a plugin	Yes?	yes but no GUI in demo	Yes, but very basic	Yes, with a GUI A modern Sieve library in PHP was developer for this	Via Cypht, and available even if server doesn't support Sieve	No (uses Procmail instead)
Mail: Search throughout all folders	Yes	Yes, via Roundcube	Yes	Yes	assigned to a developer	Missing (via Cypht)	?
JMAP support	No	No	No	No	Yes, in version 2+	Yes, via Cypht	No. See related discussion about JMAP and Virtualmin
Exchange Web Services (EWS) support	No	No	No	No	Yes	Yes, via Cypht	No
Calendar invitations by email	?	Yes	?	Yes?	No	Yes	No
Calendar	?	Yes	?	Nextcloud calendar	very basic	Tiki Calendar	No?
CalDAV	?	Yes	?	yes	No	yes	?
Contacts	Yes	Yes, via Roundcube	Yes	Yes	Yes	Tiki Contacts with interop with Cypht contacts	Yes
CardDAV	?	Yes	?	yes	read-only	yes	?

Should be analyzed:

Not included (yet), and why?

RainLoop: Activity level is too low: https://openhub.net/p/rainloop-webmail/commits/summary, and has been forked into SnappyMail
YunoHost is an interesting platform to manage apps. It's a full mail server and you can pick between Roundcube, Rainloop, Cypht etc. Not including below because it doesn't offer a distinct webmail client.
Horde IMP: Activity level is too low: https://openhub.net/p/horde/commits/summary
SOGo: Full mail distro. Is the webmail available in standalone to connect to other email servers?
SquirrelMail: Activity level too low: https://openhub.net/p/squirrelmail/commits/summary
Linagora / OpenPaaS / Team Mail Flutter
- OpenPaaS (from Linagora) is interesting and supports JMAP but AFAICT webmail client is not available to run as standalone: https://github.com/linagora/openpaas-esn/tree/master/modules/linagora.esn.messaging.email
- Linagora seems to have shifted their ressources to Team Mail Flutter (For mobile apps and there is a webmail) and work has been done to support Stalwart JMAP: https://github.com/linagora/tmail-flutter/pull/2315
  - Team Mail Flutter is great for moving forward the JMAP ecosystem but not added above because it doesn't support IMAP and SMTP (and sadly we are not yet in a predominantly JMAP world).