CardDAV

 CardDAV  is a protocol for syncing contact information, typically from personal devices like phones to services or web servers, such as your own website.

Server Software Support

 * Radicale is a Python/WSGI implementation of CalDAV and CardDAV, and also does sync over WebDAV and basic HTTP(S). It's GPL3 licensed.
 * sabre.io The open source CardDAV, CalDAV and WebDAV server.
 * Baikal Baïkal is a lightweight CalDAV + CardDAV server based on PHP, SQLite and SabreDAV.

Using Contact Lists on Our Own Site
The following was synthesized by on 2020-03-25 at 19:39 PST

During a IWC Session, there was a notion around bridging a concept of "contact lists". The source of the lists' contact wasn't important; but as long as it could provide a WebSub-enabled h-feed of h-cards. An idea floated (by ) was to provide a page that pulled from a group in a personal CardDav server that would generate h-cards that one could use to determine one's "identity".

Some consuming cases of such a feed could be the following:


 * a site that supports AutoAuth to gate a private post from the general public to a fixed list of people.
 * controlling who can send replies to a post by a site's internal logic (i.e: ACL)

A pet name for this concept is  MicroDav .