Sync Nextcloud calendars with CalDAV and contacts with CardDAV by using the account links shown in your Nextcloud web interface, then verify a test event and contact on every device.
Understand the protocols
CalDAV synchronizes calendar collections and CardDAV synchronizes address books. They are open standards supported by many desktop and mobile calendar or contacts apps. Nextcloud remains the source service for the collections, while each client keeps a local view and sends changes back through the protocol.
Find the account links
In your Nextcloud web interface, open the calendar or contacts area and look for the personal settings or synchronization information. Copy the CalDAV address for calendars and the CardDAV address for contacts as shown there. Do not guess a path from a search result: the exact endpoint can vary with the instance configuration. Use HTTPS and sign in with the account credentials or an app password when the client supports one.
Add a calendar client
Create a new CalDAV account in the calendar app on your computer or phone. Enter the server address, username, and authentication details, then choose which calendars to display. Create a test event with a distinctive title and check that it appears in the web interface and on another client. Repeat with an event edit and deletion so you know which account owns the collection.
Add a contacts client
Add a CardDAV account in the contacts app and select the address books you need. Create a test contact with a harmless value, confirm it in the web interface, and then edit it from a second device. Keep personal and shared address books separate so a client does not merge them unexpectedly.
Handle conflicts deliberately
A conflict can occur when two clients edit the same event or contact before either has synchronized. The app may keep a duplicate, prefer the later write, or show a conflict prompt; behavior depends on the client. Let pending changes finish before editing again, and compare the web version with the local version before removing a duplicate. If a client repeatedly creates copies, pause it and inspect its account settings and timezone.
Keep synchronization healthy
- Use one consistent timezone and calendar naming scheme.
- Check the client log when a collection stops updating.
- Remove old device accounts instead of leaving abandoned credentials active.
The Nextcloud comparison guide explains why CalDAV and CardDAV help avoid lock-in. Visit support when an instance-specific endpoint or authentication problem needs investigation.