History: Webmail and groupware comparison

Preview of version: 1

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:

Roundcube
SnappyMail (RainLoop fork)
Cypht

Special cases:

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

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

Kolab is added because it is behind Roundcube.
Virtualmin is added because it is the mail stack of WikiSuite (And Tiki is also a WikiSuite component)

Not included (yet), and why?

YunoHost is interesting platform to manage apps. It's a full mail server and you can pick between Roundcube Rainloop, Cypht etc. Not including because it doesn't offer a distinct webmail client
Horde IMP: need to check activity level: https://openhub.net/p/horde
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
OpenPaaS is interesting and supports JMAP but AFAICT webmail client is not available as standalone: https://github.com/linagora/openpaas-esn/tree/master/modules/linagora.esn.messaging.email
https://github.com/afterlogic/webmail-lite-8 should be analyzed

	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)	?