VCalendar

iCalendar

Filename extension	.ical, .ics, .ifb, .icalendar
Internet media type	text/calendar
Type of format	Calendar data exchange
Standard	RFC 5545 (Updated by: RFC 5546, RFC 6868, RFC 7529)
Open format?	Yes

iCalendar is a computer file format which allows Internet users to send meeting requests and tasks to other Internet users by sharing or sending files in this format through various methods. The files usually have an extension of .ics. With supporting software, such as an email reader or calendar application, recipients of an iCalendar data file can respond to the sender easily or counter-propose another meeting date/time. The file format is specified in a proposed internet standard (RFC 5545) for calendar data exchange.

ICalendar is used and supported by a large number of products, including Google Calendar, Apple Calendar (formerly iCal), IBM Lotus Notes,Yahoo! Calendar, Evolution (software), eM Client, Lightning extension for Mozilla Thunderbird and SeaMonkey, and partially by Microsoft Outlook and Novell GroupWise.

iCalendar is designed to be independent of the transport protocol. For example, certain events can be sent by traditional email or whole calendar files can be shared and edited by using a WebDav server, or SyncML. Simple web servers (using just the HTTP protocol) are often used to distribute iCalendar data about an event and to publish busy times of an individual. Publishers can embed iCalendar data in web pages using hCalendar, a 1:1 microformat representation of iCalendar in semantic (X)HTML.

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