CalDAV

Calendaring Extensions to WebDAV, or CalDAV, is an Internet standard allowing a client to access and manage calendar data along with the ability to schedule meetings with users on the same or on remote servers. It lets multiple users in different locations share, search and synchronize calendar data. It extends the WebDAV (HTTP-based protocol for data manipulation) specification and uses the iCalendar format for the calendar data. The access protocol is defined by RFC 4791. Extensions to CalDAV for scheduling are standardized as RFC 6638. The protocol is used by many important open-source applications.