Calendaring Extensions to WebDAV, or CalDAV, is an

Internet standard In computer network engineering, an Internet Standard is a normative specification of a technology or methodology applicable to the Internet. Internet Standards are created and published by the Internet Engineering Task Force (IETF). They allow ...

allowing a

client Client(s) or The Client may refer to: * Client (business) * Client (computing), hardware or software that accesses a remote service on another computer * Customer or client, a recipient of goods or services in return for monetary or other valuable ...

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 to share, search and synchronize calendar data. It extends the

WebDAV WebDAV (Web Distributed Authoring and Versioning) is a set of extensions to the Hypertext Transfer Protocol (HTTP), which allows user agents to collaboratively author contents ''directly'' in an HTTP web server by providing facilities for concu ...

(

HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, ...

-based protocol for data manipulation) specification and uses the

iCalendar The Internet Calendaring and Scheduling Core Object Specification (iCalendar) is a media type which allows users to store and exchange calendaring and scheduling information such as events, to-dos, journal entries, and free/busy information, a ...

format for the calendar data. The access protocol is defined by . Extensions to CalDAV for scheduling are standardized as . The protocol is used by many important open-source applications.

History

The ''CalDAV'' specification was first published in 2003 as an

Internet Draft An Internet Draft (I-D) is a document published by the Internet Engineering Task Force (IETF) containing preliminary technical specifications, results of networking-related research, or other technical information. Often, Internet Drafts are int ...

submitted to the Internet Engineering Task Force (

IETF The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and a ...

) by Lisa Dusseault. In March 2007, the ''CalDAV'' specification was finished and published by the IETF as RFC 4791, authored by Cyrus Daboo (

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

), Bernard Desruissaux (

Oracle An oracle is a person or agency considered to provide wise and insightful counsel or prophetic predictions, most notably including precognition of the future, inspired by deities. As such, it is a form of divination. Description The word '' ...

), and Lisa Dusseault (

CommerceNet CommerceNet is a 501(c)6 organization established in 1994 to promote electronic commerce on the Internet. The organisation initially focused on industry-wide research and programs that have advanced the commercial use of the Internet. History Comm ...

). ''CalDAV'' is designed for implementation by any

collaborative software Collaborative software or groupware is application software designed to help people working on a common task to attain their goals. One of the earliest definitions of groupware is "intentional group processes plus software to support them". As re ...

, client or server, that needs to maintain, access or share collections of events. It is developed as an

open standard An open standard is a standard that is openly accessible and usable by anyone. It is also a prerequisite to use open license, non-discrimination and extensibility. Typically, anybody can participate in the development. There is no single definition ...

to foster interoperability between software from different implementers.

Specification

The architecture of ''CalDAV'' (partially inherited from the underlying specifications) organizes the data (events, tasks, free-busy info, notes) in directories (collections), where multiple items (resources) reside. The resources and collections can be accessed by one or more users, using standard HTTP and DAV semantics to detect conflicting changes, or to provide locking. For access control the concept of ACLs are used, so each operation (view, edit, delete etc.) can be denied or granted per user. Therefore, the specification requires that CalDAV servers must support "WebDAV Access Control Protocol" (RFC 3744). The calendar resources must use

format, which allows the server to understand and process the data. Parsing the

items is necessary, because the server has to support a number of calendaring-specific operations such as doing free-busy time reports and expansion of recurring events. With this functionality, a user may synchronize their own calendar to a CalDAV server, and share it among multiple devices or with other users. The protocol also supports non-personal calendars, such as calendars for sites or organizations.

Software

Client

The list of CalDAV clients includes: * AgenDAV (Open Source multi-language CalDAV WebClient with AJAX interface) * Bloben (Open Source self hosted CalDAV web client) Bloben
/ref> * iPhone (version 3.0 or version 2.1 with Remote Calendar) * CalDavZAP (Web-based HTML5 / JavaScript application, Open Source)CalDavZAP
/ref> * CalDAV Tasksync for AndroidTaskSync
/ref> * CalDAV-Sync for AndroidCalDAV-Sync
/ref> * CalendarSync for AndroidCalendarSync
/ref> * DAVx⁵ (previously called DAVdroid) for Android (Open Source)DAVx⁵
/ref> * EVO Collaborator for Outlook add caldav sync capability to Outlook *

Evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

(Linux, Unix, Windows) *

eM Client eM Client is a Windows and macOS based email client for sending and receiving emails, managing calendars, tasks, contacts, and notes. Live chat is integrated as well. It was developed as a user-friendly alternative to existing email clients and c ...

(Windows, macOS) * gSyncitFieldston Software
/ref> (Sync Microsoft Outlook with mobile/tablet device) * Horde GroupwareHorde Groupware
/ref> * iCal4OL (No longer available for new customers) *

iCal Calendar is a personal calendar app made by Apple Inc. that runs on both the macOS desktop operating system and the iOS mobile operating system. It offers online cloud backup of calendars using Apple's iCloud service, or can synchronize with ...

/Calendar.app (Since Mac OS X Leopard !V 10.5) * iCal Import/Export CalDAV for AndroidiCal Import/Export CalDAV
/ref> *

Mailfence Mailfence is an encrypted email service that offers OpenPGP based end-to-end encryption and digital signatures. It was launched in November 2013 by ContactOffice Group, which has been operating an online collaboration suite for universities and ...

CalDAV client through iCAL/vCAL *

Sunbird Sunbirds and spiderhunters make up the family Nectariniidae of passerine birds. They are small, slender passerines from the Old World, usually with downward-curved bills. Many are brightly coloured, often with iridescent feathers, particularly i ...

Thunderbird Thunderbird, thunder bird or thunderbirds may refer to: * Thunderbird (mythology), a legendary creature in certain North American indigenous peoples' history and culture * Ford Thunderbird, a car Birds * Dromornithidae, extinct flightless birds ...

with the

Lightning Lightning is a naturally occurring electrostatic discharge during which two electric charge, electrically charged regions, both in the atmosphere or with one on the land, ground, temporarily neutralize themselves, causing the instantaneous ...

extension (Linux, Windows, Unix, Mac OS X) * OpenSync for Android * Outlook CalDav Synchronizer (open source) adds CalDAV support to Microsoft OutlookOutlook CalDav Synchronizer
/ref> * vdirsyncer synchronizes calendars (and addressbooks) between two storages, e. g. CalDAV (CardDAV) server with a local folder or file. *

Windows 10 Windows 10 is a major release of Microsoft's Windows NT operating system. It is the direct successor to Windows 8.1, which was released nearly two years earlier. It was released to manufacturing on July 15, 2015, and later to retail on J ...

, though restricted to certain providers

Server

The list of CalDAV servers includes: *

Darwin Calendar Server * Baïkal, a lightweight CalDAV and CardDAV server. * Bedework (former UWCalendar) * Bynari Collaboration Suite * Chandler Server (Cosmo) *

CommuniGate Pro CommuniGate Pro (CGatePro) is a highly scalable carrier grade unified communications server, as well as a development platform. The system is Internet Protocol based. The server is a single process, multi-threaded application written entirely in ...

Since version 5.2 *

Cyrus IMAP server The Cyrus IMAP server is electronic mail server software developed by Carnegie Mellon University. It differs from other Internet Message Access Protocol (IMAP) server implementations in that it is generally intended to be run on sealed servers, ...

since version 2.4.17 *

DAViCal DAViCal is a server for calendar sharing. It is an implementation of the CalDAV protocol which is designed for storing calendaring resources on a remote shared server. Although the events are stored in a SQL database the information between client ...

* DPCalendar * DavMail * Daylite CalDAV Server * Dingo Calendar Server * EGroupware Since version 1.6 * EVO Mail Server * Fabasoft Folio Cloud *

Google Calendar Google Calendar is a time-management and scheduling calendar service developed by Google. It became available in beta release April 13, 2006, and in general release in July 2009, on the web and as mobile apps for the Android and iOS platforms. ...

* Horde Groupware * Icewarp-E-Mail-Server Since version 8.x *

Kerio Connect Kerio Technologies, Inc. is a former technology company specializing in collaboration software and unified threat management for small and medium organizations. Founded in 2001, Kerio is headquartered in San Jose, California. In January 2017, GFI ...

* MDaemon Email Server *

* mod caldav *

Nextcloud Nextcloud is a suite of client-server software for creating and using file hosting services. Nextcloud provides functionally similar to Dropbox, Office 365 or Google Drive when used with integrated office suite solutions Collabora Online or Only ...

Open-Xchange Open-Xchange is a web-based communication, collaboration and office productivity software suite, which enables full integration of email, documents, scheduling and social media. History Founded in 2005 by Rafael Laguna and Frank Hoberg, the softw ...

Oracle Beehive Oracle Beehive is collaboration platform software developed by Oracle Corporation that combines email, team collaboration, instant messaging, and conferencing in a single solution. It can be deployed on-premises as licensed software or subscribed ...

* Oracle Siebel CRM * Oracle Communications Calendar Server *

ownCloud ownCloud is an open-source software product for sharing and syncing of files in distributed and federated enterprise scenarios. It allows companies and remote end-users to organize their documents on servers, computers and mobile devices and w ...

* Radicale (CalDAV) * SOGo * SabreDAV *

Scalix Scalix is an e-mail and groupware server that runs on Linux, licensed under the Scalix Public License (SPL). The software provides e-mail, group calendaring and other collaborative software, which are standard in groupware. It can be also be ac ...

* Sun Java Calendar Server
Synology Calendar
* Synovel CollabSuite * Xandikos * Yahoo Calendar * Zarafa Since la version 6.30.0 *

Zimbra Zimbra Collaboration, formerly known as the Zimbra Collaboration Suite (ZCS) before 2019, is a collaborative software suite that includes an email server and a web client. Zimbra was initially developed by LiquidSys, which changed their name ...

Since version 4.5 * sync!Egw * Zoho CRM

References

External links

CalDAV Resource Site

CalConnect, The Calendaring and Scheduling Consortium

WebDAV Resources

Open Calendar Sharing and Scheduling with CalDAV
L. Dusseault, J. Whitehead, IEEE Internet Computing 9(2)

RFCs

* – HTTP * – WebDAV Access Control Protocol * – CalDAV * – WebDAV * – iCalendar * – iTIP {{DEFAULTSORT:Caldav Application layer protocols Calendaring standards