This web site describes the CardDAV protocol, and includes details about the protocol, related standards, CardDAV products and other related information. It is kindly being hosted by The Calendaring and Scheduling Consortium.

CardDAV is an address book client/server protocol designed to allow users to access and share contact data on a server.

The CardDAV protocol has been standardized by the
IETF and published as RFC 6352.

The new version of vCard (vCard 4) has been published by the I
ETF as RFC 6350, and the XML Representation of vCard (xCard) as RFC 6351.