Semantic Coherence: Roundcube – Signal Evidence & AI Readability

Be aware of scam emails appearing to be sent from Roundcube Webmail!
Read how to protect you and your users.

[H1] Roundcube webmail...

...is a browser-based multilingual IMAP client with an application-like user interface.
It provides full functionality you expect from an email client, including MIME support,
address book, folder manipulation, message searching and spell checking.
More information

[H2] Features

Drag-&-drop message management
Full support for MIME and HTML messages
Multiple sender identities
Full featured address book with groups and LDAP connectors
Find-as-you-type address book integration
Threaded message listing
IDNA and SMTPUTF8 support
Spell checking
Responsive skin (multi-device support)
Shared/global IMAP folders
Support for access control lists (ACL)
Built-in caching for fast mailbox access
Unlimited users and messages
Import/export functions
Plug-in API for flexible extensions
XSS attack protection
Support for PGP encryption
Complete list of features

Security updates 1.6.16 and 1.7.1 released
24 May 2026

Roundcube 1.7.0 released
10 May 2026

Security updates 1.7-rc6, 1.6.15 and 1.5.15 released
29 March 2026

Security updates 1.7-rc5, 1.6.14 and 1.5.14 released
18 March 2026

Roundcube 1.7 RC4 released
13 February 2026

[H1] About the Roundcube webmail project

This project is a free and open source webmail solution with a desktop-like user interface which is easy to install/configure
and that runs on a standard LAMPP server. The skins use the latest web standards to render a functional and customizable UI.
Roundcube includes other sophisticated open-source libraries such as PEAR,
an IMAP library derived from IlohaMail,
the TinyMCE rich text editor,
Googiespell library for spell checking and
the HTML5-PHP sanitizer by Masterminds.

[H2] Features

[H3] Main Features

Drag-&-drop message management
Full support for MIME and HTML messages
Multiple sender identities
Full featured address book with groups and LDAP connectors
Threaded message listing
IDNA and SMTPUTF8 support
Spell checking
Canned response templates
IMAP folder management
Shared/global IMAP folders
Support for external SMTP server
Support for access control lists (ACL)
Built-in caching for fast mailbox access
Unlimited users and messages
Import/export functions
Template system for custom skins
Plug-in API for flexible extensions

[H3] Security

Sophisticated privacy protection
Brute-force login attack prevention
XSS attack protection
Support for PGP encryption
OAuth/XOauth login support

[H3] User Interface

Available in over 80 languages
Three column view
Responsive skin (multi-device support)
Light and dark interface modes
Attachment previews
Find-as-you-type address book integration
Searching messages and contacts

[H3] 3rd Party Additions

Advanced search
Keyboard shortcuts
Calendar module
Two-factor authentication
Multiple accounts
Browse all 3rd party plugins and skins available on Packagist.
See the development roadmap for more.

[H2] Server Requirements

Apache, Lighttpd, Nginx, IIS, Cherokee or Hiawatha web server
PHP Version 8.1 or greater1
MySQL/MariaDB, PostgreSQL or SQLite database
SMTP server and IMAP server with IMAP4 rev1 support
More detailed list of requirements
1. Roundcube supports versions of PHP available at the time of each major release. See the version history for more information.

[H2] License

Roundcube Webmail is released under the GNU General Public License
version 3 or any later version with exceptions for skins and plugins.

Everyone is welcome to download and use it, deploy it and to re-distribute it.
The code is provided «as-is» and in no event shall the copyright
owner or contributors be liable for any direct, indirect, incidental,
special, exemplary, or consequential damages.
More details about licensing and the exceptions for skins and plug-ins

[H2] Services using and supporting Roundcube

There are thousands of services that make use of Roundcube to provide
webmail to millions of users. We love to see our application in so many hands
and believe it is essential for society at large to have Open Source software
available for a crucial task such as communication.

Below is a list of services that not only use, but actively contribute to
Roundcube and where usage of those services helps to improve and further develop
Roundcube webmail. These are the services that make it possible for us to
continue improving our software and to make it freely available for everybody.
Preferring one of these services will help them to further support us.

Nextcloud
develops software for decentralized and federated clouds as alternative to centralized cloud services.

Since 2023 it is the new home of Roundcube and fosters the growth and improvement of the project.

KolabNow
is the highly security and privacy centric business and personal groupware hosting from a data centre
in central Switzerland. Run by Apheleia IT,
the developers of Kolab,
KolabNow offers Mail, Calendar, Tasks and File Cloud on all platforms, including mobile.

HostingU2
is contributing web hosting services to run Roundcube's free and privacy-safe spell checking service.

[H1] Find answers to your questions

IMPORTANT! If you have problems with your email account (e.g. cannot log in, emails got lost, etc.)
or if you have questions how to configure your Outlook or mobile phone to get email, this isn't the
right place to ask. Roundcube is not a service but free software which somebody installed for you.

Please contact your internet hosting provider or IT responsible instead. If you don't know who this
might be, please review your bills and find out who you're paying for email and webhosting services.
Native mobile apps? This project does not provide support for any native apps for mobile devices.
We're not affiliated with any such application and we do not recommend any. Be careful, some of these
apps use project's name without permission and their quality or intentions are questionable.
For issues concerning the software itself, there are several ways to get help on questions about Roundcube,
its installation, configuration and ongoing development. Please choose from the following:

[H2] Documentation Wiki
To get additional information on how to set up Roundcube and to find out what all those
config parameters are good for, our Wiki will help.

[H2] Official enterprise support
Official support for Roundcube is available from the steward of the Roundcube project, Nextcloud GmbH.
The support is tailored specifically for mail providers running large instances with thousands to millions of end users.
Optional email server solutions as well as PGP encrypted email are available with this offering.
Learn more.

[H2] Community forum
Get help at our web-based message board. Different topics like Issues and Bugs, Feature Requests
as well as general discussions about the project can be found here:
roundcubeforum.net
Please also check our bug tracker
for already reported and discussed bugs and feature requests.

[H2] Mailing lists
If you have general questions, comments, or suggestions please send them
to our mailing lists. The following mailing lists are available for this project:

[H3] users
All topics related to the installation, use and administration of Roundcube Webmail.

[H3] announce
Read-only list with announcements like new versions, security bugs and more. Moderated by the project administrator.

[H3] dev
Discussion of the ongoing development and next steps. Please don't post bug reports here but file an issue
at our bug tracker instead.
In order to post to the lists you need to subscribe first.

[H3] Archives
All messages can be found in the archive at lists.roundcube.net.

[H2] IRC chat
Join #roundcube on libera.chat
to ask a question or to just hang out with other Roundcube users.

Bug tracker
Wiki pages
Online forum
Mailing lists

Find freelance developers
Upwork is the world's largest online workplace, enabling businesses and freelancers to work together
on-demand via the Internet.Visit Upwork today
to find development talent for your Roundcube projects!

Apheleia consulting
Apheleia IT
employs several Roundcube developers for their E-Mail and Groupware solutions that integrates Roundcube into their web client
(Kolab Now as a hosted solution, and
Kolab in general).
In some special cases they offer professional support and services for Roundcube, too.

You can contact them with your request by sending an e-mail to [email protected].

[H1] Impressions of Roundcube's User Interface
Below are some screenshots of Roundcube in use. Additional skins are available on Packagist. You can also create your own skin or extend an existing skin to make Roundcube look just right for you.

[H2] Elastic
Author: Aleksander Machniak
Released with Roundcube version 1.4.0, Elastic is Roundcube's first official responsive skin. It has support for desktops, tablets and phones.

desktop

tablet

phone

[IMG: Mailbox view]

[IMG: Message viewer with privacy protection]

[IMG: Multilingual display]

[IMG: Dark mode support]

[IMG: Compose HTML mails with attachments]

[IMG: Address book with LDAP integration]

[IMG: Extensible contact management form]

[IMG: Versatile user settings]

[IMG: Easy IMAP folder management]

[IMG: Sender identities with signature]

[IMG: Plugins like Enigma for signing and encrypting emails]

[IMG: ...or Managesieve filter configuration]

[IMG: Mailbox view]

[IMG: Message viewer with privacy protection]

[IMG: Multilingual display]

[IMG: Dark mode support]

[IMG: Compose HTML mails with attachments]

[IMG: Address book with LDAP integration]

[IMG: Extensible contact management form]

[IMG: Versatile user settings]

[IMG: Easy IMAP folder management]

[IMG: Sender identities with signature]

[IMG: Plugins like Enigma for signing and encrypting emails]

[IMG: ...or Managesieve filter configuration]

[IMG: Mailbox view]

[IMG: Message viewer with privacy protection]

[IMG: Multilingual display]

[IMG: Dark mode support]

[IMG: Compose HTML mails with attachments]

[IMG: Address book with LDAP integration]

[IMG: Extensible contact management form]

[IMG: Versatile user settings]

[IMG: Easy IMAP folder management]

[IMG: Sender identities with signature]

[IMG: Plugins like Enigma for signing and encrypting emails]

[IMG: ...or Managesieve filter configuration]

[H2] Larry
Author: FLINT / Büro für Gestaltung, Switzerland
Released with Roundcube version 0.8.0, Larry provides visual impact thanks to its use of color and specially designed graphics.Support deprecated as of Roundcube 1.6.0. Available via Composer.

[IMG: Three-paned mailbox view (vertical)]

[IMG: Three-paned mailbox view (horizontal)]

[IMG: List only mailbox view]

[IMG: Message viewer with privacy protection]

[IMG: Multilingual display]

[IMG: Compose HTML mails with attachments]

[IMG: Address book with LDAP integration]

[IMG: Extensible contact management form]

[IMG: Versatile user settings]

[IMG: Easy IMAP folder management]

[IMG: Sender identities with signature]

[IMG: Plugins like Enigma for signing and encrypting emails]

[IMG: ...or Managesieve filter configuration]

[H2] Classic
Author: The Roundcube Dev Team
Formally known as Default, renamed to Classic as of Roundcube version 0.8.0, this is Roundcube's original skin.Support deprecated as of Roundcube 1.4.0. Available via Composer.

[IMG: Three-paned mailbox view (vertical)]

[IMG: Three-paned mailbox view (horizontal)]

[IMG: List only mailbox view]

[IMG: Message viewer with privacy protection]

[IMG: Multilingual display]

[IMG: Compose HTML mails with attachments]

[IMG: Address book with LDAP integration]

[IMG: Extensible contact management form]

[IMG: Versatile user settings]

[IMG: Easy IMAP folder management]

[IMG: Sender identities with signature]

[IMG: Plugins like Enigma for signing and encrypting emails]

[IMG: ...or Managesieve filter configuration]

Note: The following plugins, distributed with Roundcube, were active when the screenshots where taken: acl, archive, enigma, help, managesieve, markasjunk, password, and vcard_attachments.