Baïkal is a lightweight CalDAV+CardDAV server. It offers an extensive web interface with easy management of users, address books and calendars. It is fast and simple to install and only needs a basic php capable server. The data can be stored in a MySQL or a SQLite database.

Baïkal allows to seamlessly access your contacts and calendars from every device. It is compatible with iOS, Mac OS X, DAVx5 on Android, Mozilla Thunderbird and every other CalDAV and CardDAV capable application. Protect your privacy by hosting calendars and contacts yourself - with Baïkal.

Baïkal is free and open-source, developed by Net Gusto and fruux together with many contributors. It is released under the GNU GPL v3 license.
Baïkal is powered by sabre/dav, while offering an administrative interface for easy management.