Bootstrapping

CalDAV service discovery — how clients locate the server and user’s calendar data.

Well-Known URLs

The simplest discovery method. The client makes a GET or PROPFIND request to:

https://example.com/.well-known/caldav

The server redirects (302/307) to the actual CalDAV endpoint.

DNS SRV Records

Servers can advertise CalDAV via DNS SRV records:

_caldavs._tcp.example.com. SRV 0 1 443 caldav.example.com.

The client looks up the SRV record to find the CalDAV server host and port.

Principal Discovery

After reaching the CalDAV endpoint, PROPFIND for current-user-principal:

<D:propfind xmlns:D="DAV:">
  <D:prop><D:current-user-principal/></D:prop>
</D:propfind>

Calendar Home Set

From the principal URL, PROPFIND for calendar-home-set:

<D:propfind xmlns:D="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
  <D:prop><C:calendar-home-set/></D:prop>
</D:propfind>

This returns the URL of the collection containing all the user’s calendars.