How do I sync with CalDAV calendars?
CalDAV is an open standard used by iCloud, Nextcloud, Fastmail, Synology, and others. Hubhus supports full two-way sync — events flow in both directions automatically, keeping availability accurate across systems.
TL;DR
CalDAV is always full two-way — you can't pick one direction only. Add the calendar at Calendar → Settings → CalDAV calendars, then link it to a resource at Calendar → Settings → Synchronization. Sync runs every 5 minutes (not real-time) covering one year forward. Use app-specific passwords for iCloud and Fastmail. For Google Calendar, use the dedicated Google Workspace integration instead.
Get started in 4 steps
Go to Calendar → Settings → CalDAV calendars and click + New CalDAV calendar.
Enter the CalDAV URL, username, and password (use an app-specific password for iCloud/Fastmail). Leave Name blank to auto-fetch it from the provider.
Go to Calendar → Settings → Synchronization → find your CalDAV calendar under "External calendars" → click Link calendar → select the Hubhus resource to link it to.
Wait up to 5 minutes for the first sync to complete. Hubhus polls every 5 minutes and syncs one year forward in both directions.
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Provider notes
iCloud: Requires an app-specific password (generated in Apple ID settings). Full read/write supported. Syncing can be slightly slow due to Apple throttling.
Nextcloud / ownCloud: Fully supported, most reliable for two-way sync. Use primary CalDAV URL from user settings.
Fastmail: Fully supported with app password. CalDAV URL found in Fastmail settings.
Synology: Supported. Shared/group calendars may have limited write access — use personal calendars for best results.
Amparex: Supports CalDAV integration. Full read/write is supported. Consult Amparex documentation for the correct CalDAV URL and use the provided authentication credentials.
Google Calendar: Not recommended via CalDAV — Google restricts write access. Use the dedicated Google Workspace integration instead.
How sync works in both directions
CalDAV → Hubhus: External events are imported and shown on the linked resource's calendar (marked as external). Changes and deletions in CalDAV are reflected in Hubhus. If a Hubhus-created event is deleted in CalDAV, the resource is unassigned (if last resource, the event is deleted).
Hubhus → CalDAV: New and updated Hubhus events are pushed to the external CalDAV calendar. Events deleted in Hubhus are also deleted from CalDAV (only applies to events originally created in Hubhus — external-native events are never deleted by Hubhus).
Troubleshooting
Events not appearing: Wait up to 5 minutes. Check that the calendar is linked to a resource. Verify URL and credentials are valid.
Authentication failed: Use an app-specific password if required. Confirm the URL format is correct (wrong URL can cause auth errors). Try using email address as username.
Changes from Hubhus not reaching external calendar: Provider may restrict write access. Use a supported provider like Nextcloud, iCloud, or Fastmail.
Resource unassigned unexpectedly: The event was likely deleted in the external calendar. Re-assign in Hubhus. Tip: always delete shared events from Hubhus, not from the external calendar.
Common searches
caldav sync • icloud calendar hubhus • nextcloud sync • external calendar • two-way calendar • app password caldav • link calendar resource
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