CardDAV-Sync is a CardDAV client for Android to synchronize contacts. Due to its implementation as sync adapter it integrates seamlessly with the default contacts app.
(Also check out CalDAV-Sync)

Important note for Android 4.1 and Samsung users: To prevent the removal of your accounts on reboot install this app:
https://play.google.com/store/apps/details?id=org.dmfs.jb.workaround.carddavsync
At present, Samsung users still need this workaround, even on recent devices.

Also note that many Android 4.x and 5.0 devices need the workaround to prevent removal of accounts during an app update.

HTC One users please check out this site first: http://dmfs.org/wiki/index.php?title=HTC_Sense_issue

Get support and news via Twitter https://twitter.com/dmfs_org

If you find a bug send me an email please. Without detailed error description I often can't do anything especially when I can't reproduce it. It's also possible that your server has a bug that CardDAV-Sync can not (yet) tolerate or work around. If you report bugs I can fix them quickly and everyone will benefit.

This is the paid version of CardDAV-Sync. It equals the free version except that it syncs more fields. Visit my website for details.

Please uninstall the free version before you install the paid one (and vice versa).

For users which are unable to edit or create synced contacts I published an editor at the market. Just search for "Contact Editor" or see our website.

Once this app reaches version 1.0, I'll make it open source.
See http://dmfs.org/wiki/index.php?title=Open_source_status for details on the open source status.

Features:

* Sync contacts from a CardDAV-server (tested and reported to work with DAViCal, SOGo, egroupware, Zimbra, david.fx, Fruux, ownCloud ... and more. See our website for details)

* supports multiple address books per account

* basic support for self-signed certificates

* auto-provisioning

* two-way-sync

* syncs names, phone numbers, email addresses, postal addresses, photos, birthdays (but please visit "date formats" on my website first), notes, instant messengers, organizations, nicknames, categories (groups), phonetic names, related names and websites

* automatic address book discovery (works with most servers in default configuration)

* one-way-sync of Apple-style groups

* Support for Apple-style custom labels (X-ABLABEL)

* stores passwords encrypted

* supports efficient sync-collection request

* supports client certificate authentication

* import wizard for contacts from other accounts