jCal

jCal is a JSON-based encoding of iCalendar data. It provides a machine-readable representation of calendar information intended for web applications and APIs that handle events, tasks, and other calendar components. The format was defined by the Internet Engineering Task Force as The iCalendar Object Representation in JSON (jCal) to complement the traditional iCalendar text format (ICS).

jCal encodes the iCalendar data model into a nested JSON structure. A jCal document represents a vcalendar object containing properties and subcomponents such as vevent, vtodo, vjournal, and vtimezone. According to the specification, each component is represented as a JSON array whose first element is the component name, followed by an array of property entries and, optionally, nested components. Each property entry is itself a four-element array: the property name, a parameters object, the value type, and the value.

Common components and properties include vevent with uid, dtstart, dtend, summary, and description, and vtimezone for time zone definitions. Time zone information is preserved by including vtimezone components in the vcalendar. The format is designed to be easy to parse in JavaScript and other languages, serving as a convenient interchange format between servers and clients in web-based calendar integrations.

Usage and compatibility: jCal is used where JSON is the preferred data interchange format for calendar data, such as web APIs and calendar clients. Libraries exist to parse and generate jCal in many languages, and conversion to and from ICS is possible. While jCal captures much of iCalendar’s semantics, some complex features or vendor-specific extensions may not round-trip perfectly.