CalDAV CardDAV
CalDAV (Calendar Extensions to WebDAV) and CardDAV (vCard Extensions to WebDAV) are open standards-based protocols for synchronizing calendar and contact data over the internet, respectively. They extend the WebDAV protocol to enable clients (e.g., email apps, mobile devices) to access and manage calendar events and address book entries stored on servers, facilitating cross-platform compatibility and interoperability without proprietary lock-in.
Developers should learn and use CalDAV and CardDAV when building applications that require calendar or contact synchronization, such as email clients, productivity tools, or personal information managers, especially in environments that prioritize open standards and interoperability. They are essential for integrating with services like Nextcloud, ownCloud, or Apple iCloud, and are widely supported in enterprise and personal contexts to avoid vendor-specific APIs.