ownCloud

DAVdroid has been successfully tested with ownCloud.

ownCloud is a PHP-based file sync and share solution. It can be extended with apps for Contacts, Calendars and Tasks.

DAVdroid settings

To use both CalDAV and CardDAV in the same account and just using the host name as URL, configure well-known URLs (recommended).

OwnCloud 9:
Base URL:/remote.php/dav/ (e.g. https://server.example/owncloud/remote.php/dav/)

OwnCloud 8 and below:
For CalDAV use: /remote.php/caldav/ (e.g. https://server.example/owncloud/remote.php/caldav/)
For CardDAV use: /remote.php/carddav/

Contact group method: groups are per-contact categories

User name and password: same as in ownCloud
(LDAP authentication may cause problems with certain OwnCloud apps)

Troubleshooting

Most problems can be fixed by upgrading to the newest OwnCloud version (don't forget to update the Contacts, Calendar and Task app, too).

See also: How to fix CalDAV|CardDAV|WebDAV problems