Calendar and Contacts Server

The open source Calendar and Contacts Server project is a standards-compliant server implementing the CalDAV and CardDAV protocols. It provides a shared location on the network allowing multiple users to store and edit calendaring and contact information.

CalDAV is an Internet standard allowing a client to access scheduling information on a remote server. It extends the WebDAV (an HTTP-based protocol for data manipulation) specification and uses the iCalendar format for the data. The protocol is defined by RFC 4791. It allows multiple clients access to the same information thus allowing cooperative planning and information sharing. Many server and client applications support the protocol.

CardDAV is an address book client/server protocol designed to allow users to access and share contact data on a server. The CardDAV protocol is defined by RFC 6352.

The sources are available under the terms of the Apache License, Version 2.0.


The following sub-projects are hosted with CalendarServer:

What To Download

  • If you would like to get involved with Calendar and Contacts Server development, see the QuickStart page for how to check out trunk. All submitted diffs should be against current trunk.
  • If you would like to download a version of Calendar and Contacts Server to run on a server, look at this list of release branches. Find the most recent branch in the list, and then download it by running in a shell:

      git clone -b CalendarServer-X.Y


Getting Involved