CalDAV Provider Guide

This guide helps you find and verify the CalDAV URL for your calendar server. Use it alongside Calendar Sync when setting up a CalDAV Calendar Account.

What is CalDAV

CalDAV (Calendar Distributed Authoring and Versioning) is an open standard protocol for accessing and synchronising calendars over the internet. It is widely supported by self-hosted and cloud calendar servers.

Understanding CalDAV URLs

URL Structure

A CalDAV URL points directly to a specific calendar on the server:

https://server.example.com/dav-path/username/calendar-name/
  • Protocol: always https:// (or http:// for local servers)

  • Server: hostname or IP address of your CalDAV server

  • DAV Path: the path to the CalDAV service endpoint (varies by implementation)

  • Username: your CalDAV account username

  • Calendar Name: the specific calendar identifier

  • Trailing slash: required by most CalDAV implementations

Trailing Slash

Most CalDAV servers require the URL to end with a trailing slash. Without it, you may see "Calendar not found" or "Invalid URL" errors.

Correct:

https://caldav.example.com/dav/calendars/john/personal/

Incorrect:

https://caldav.example.com/dav/calendars/john/personal

Port Numbers

Some servers run on non-standard ports. Include the port in the URL when necessary:

http://localhost:5232/username/calendar/

Common URL Patterns

Standard URL patterns for popular CalDAV providers. Replace placeholders with your actual values.

Provider URL Pattern Notes

Nextcloud

https://your-nextcloud.com/remote.php/dav/calendars/USERNAME/CALENDAR_NAME/

USERNAME is your Nextcloud username; CALENDAR_NAME is the calendar’s internal ID (visible in Nextcloud calendar settings)

Fastmail

https://caldav.fastmail.com/dav/principals/user/EMAIL/

Use your full Fastmail email address as the username

Radicale

http://localhost:5232/USERNAME/CALENDAR_NAME/

Default port is 5232; replace with your server hostname if not running locally

SOGo

https://sogo.example.com/SOGo/dav/USERNAME/Calendar/CALENDAR_ID/

Replace with your SOGo server hostname; CALENDAR_ID is visible in SOGo calendar settings

Apple iCloud

See your iCloud calendar settings

Apple iCloud CalDAV requires an app-specific password; the URL is provided in iCloud account settings under "Set Up CalDAV"

These patterns are starting points. Verify the exact URL format with your provider’s documentation.

Finding Your CalDAV URL

If your provider is not listed above, use these general discovery steps:

  1. Check provider documentation — Most CalDAV servers document their URL structure in setup guides or help articles.

  2. Contact your administrator — If using a company-hosted server, ask your IT team for the correct URL.

  3. Use a desktop CalDAV client — Configure the same account in Thunderbird, macOS Calendar, or GNOME Evolution and inspect the connection settings for the URL format.

  4. Try CalDAV autodiscovery — Some servers support autodiscovery at https://your-server/.well-known/caldav.

Troubleshooting

"Calendar not found" or "Invalid URL"

Causes:

  • Incorrect CalDAV URL structure

  • Missing trailing slash

  • Wrong calendar name or identifier

  • Calendar has been deleted or renamed

Solutions:

  • Verify the URL ends with a trailing slash: https://server/path/calendar/

  • Check that the calendar name matches exactly (case-sensitive on some servers)

  • Log into the CalDAV web interface and confirm the calendar exists

  • Re-copy the URL from your provider’s settings page

"Authentication failed" or "Invalid credentials"

Causes:

  • Incorrect username or password

  • Username format mismatch (email address vs. username)

  • Two-factor authentication enabled without an app-specific password

  • Account locked or disabled

Solutions:

  • Verify the username format — some providers require your full email address

  • Create an app-specific password in your provider’s security settings and use that instead of your main password

  • Check that your CalDAV account is active and not locked

Security Best Practices

Use App Passwords

When available, use app-specific passwords instead of your main account password. App passwords:

  • Limit scope to calendar access only

  • Can be revoked without changing your main password

  • Provide a better security audit trail

  • Are compatible with accounts that have two-factor authentication enabled

Use HTTPS

Always use HTTPS for CalDAV connections to protect your credentials and calendar data in transit. For self-hosted servers, use Let’s Encrypt for a free SSL certificate.

Next Steps

If you encounter a CalDAV connection issue not covered here, check your provider’s documentation or contact their support team for provider-specific assistance.

Content is available under GNU Free Documentation License 1.3 or later unless otherwise noted.