Nextcloud Calendar and Contacts

Nextcloud is much more than a file storage solution – it’s a complete self-hosted collaboration platform. Many users initially think of it as a personal Dropbox or Google Drive alternative, but its true power lies in the ecosystem of apps that transform it into a fully private digital workspace. Among the most essential of these apps are Calendar and Contacts, which implement the open standards CalDAV and CardDAV.

These protocols allow seamless synchronization of calendar events and address books across all your devices – desktops, laptops, smartphones, and tablets – without relying on any third-party service. By using Nextcloud for calendars and contacts, you retain full ownership and control of your data, while still enjoying the convenience of cloud-like functionality.

For tech-savvy users, Nextcloud Calendar and Contacts offer much more than basic syncing. You can manage shared calendars for teams or projects, define granular permissions for viewing or editing, integrate with tasks, mail, and notifications, and even extend the functionality via apps and API access. The system is also fully compatible with modern two-factor authentication workflows – all under your own control.

Enabling Calendar and Contacts Apps

Even in an existing Nextcloud installation, it’s important to verify that the Calendar and Contacts apps are installed and activated, because these apps provide the underlying CalDAV and CardDAV endpoints that allow any client to synchronize events and contacts.

To check or enable the apps:

  • Navigate to Settings → Apps → Organization. The Calendar and Contacts apps are listed here among the core Nextcloud apps.
  • If the apps are disabled, simply click Enable. This will install any necessary dependencies automatically.
  • Once enabled, Nextcloud creates the corresponding DAV endpoints in the background. For example, the Calendar app will generate a URL structure under /remote.php/dav/calendars/<username>/, while the Contacts app uses /remote.php/dav/addressbooks/users/<username>/. These endpoints are fully compatible with all CalDAV and CardDAV clients.
  • Enabling the apps also allows sharing and permission management. You can define which users or groups can view or edit specific calendars or address books, which is essential for team collaboration.

In addition, enabling these apps activates internal Nextcloud features integration of contacts with the Mail app, making your Nextcloud instance more functional and interconnected.

Using App Passwords for Calendar and Contacts

When you enable Two-Factor Authentication (2FA/OTP) in Nextcloud, your main account password is no longer sufficient for external apps and clients like Thunderbird, DAVx⁵, or iOS/macOS Calendar. This is where App Passwords come in: they allow secure access to specific services without compromising your main account or OTP setup.

Why App Passwords Matter

  • Security: Your primary password remains protected. Even if a device is lost or compromised, the attacker cannot use your main password to log in elsewhere.
  • Granularity: You can create one password per device or client, making it easy to revoke access individually.
  • OTP Compatibility: Many clients don’t support OTP prompts directly. App passwords provide a secure workaround that integrates seamlessly with CalDAV and CardDAV.
  • Auditability: Nextcloud logs App Password usage, helping you monitor active connections and detect unusual activity.

Creating an App Password

  • Click Create new app password. Give it a descriptive name, e.g., "DAVx⁵ Calendar" or "Thunderbird Contacts".
  • Go to Settings → Security → App Passwords in your Nextcloud web interface.
  • For security reasons, you need to enter your personal Nextcloud password again in order to generate an app password.
  • In the following step, the long random app password will be generated automatically. The username will match your Nextcloud username. Warning: the password is only displayed at this step, so it is strongly recommended to save it in a password manager.

Nextcloud App Passwords Overview

ConceptRecommendation
Device/ClientUse a unique app password per device (Thunderbird, phone, tablet, etc.)
LoginUse Nextcloud username + app password instead of main password
SecurityKeep passwords secret, review regularly, revoke unused ones
Lost/Retired DeviceRevoke its password without affecting others
BenefitsSecure sync of calendars and contacts, OTP-compatible, easy rotation

Exporting Individual Calendars from Google

To export a calendar from Google:

  1. Open Google Calendar in a web browser.
  2. Click the gear icon → Settings.
  3. In the left menu, select Import & export.
  4. Under Export, click Export. This downloads a ZIP file containing your calendars in iCal (.ics) format.
  5. Extract the ZIP to access the individual .ics files. Each file represents one calendar.

Note: If you have multiple calendars, you need to repeat this process for each calendar to export them all.

These .ics files can then be imported into Nextcloud or any other CalDAV-compatible client.

Importing an iCal (.ics) File into Nextcloud Calendar

  1. Open Nextcloud in a web browser and go to the Calendar app.
  2. Click the Settings gear icon or the three-dot menu, then select Import.
  3. Choose the .ics file you exported from Google.
  4. Select the calendar you want to import it into, or create a new one.
  5. Click Import to add the events.
You can import the events into an existing calendar or create a new one. If you choose New Calendar, the original .ics filename will be used as the calendar name.
During the import process, the blue progress bar moves from left to right. This can take several minutes, and you should keep the window open to avoid interrupting the import.
After a successful import, a notification appears in the top-right corner showing how many calendar entries were imported.

The events from the .ics file will now appear in your Nextcloud calendar. Repeat for each calendar if you exported multiple .ics files.

Sharing Nextcloud Calendars with Other Users

To share a calendar with other users in your Nextcloud instance:

  1. Open the Calendar app.
  2. Hover over the calendar you wish to share and click the Share icon.
  3. Enter the username or group name of the user(s) you want to share with.
  4. Choose the permission level:
    • Read – users can only view events.
    • Read & Write (can edit) – users can view and edit events.
  5. The selected users will now have access to the calendar with the specified permissions.

Migrating Google Contacts to Nextcloud

  • Export from Google Contacts
    • Open Google Contacts in a web browser.
    • Select the contacts or groups you want to export.
    • Click Export → choose vCard (for iOS/Contacts). This downloads a .vcf file.
    • If you have multiple contact groups, repeat the process for each group.
  • Import into Nextcloud Contacts
    • Open Nextcloud → Contacts app.
    • Click the gear icon → Import.
    • Select the .vcf file from Google.
    • Choose an existing address book or create a new one. The imported contacts appear immediately.
    • Repeat for each .vcf file if you exported multiple groups.
  • Sync with Android via DAVx⁵
    • Install DAVx⁵.
    • Add a new CardDAV account pointing to your Nextcloud server.
    • Use your Nextcloud username and App Password.
    • Contacts will now appear in your Android Contacts app and remain synchronized.

Tip: After import, verify that duplicates are merged and groups/tags are preserved.

Handling Groups in Nextcloud

Nextcloud Contacts lets you organize contacts into groups, and there are two main methods:

Groups are Separate vCards
Each group is stored as its own vCard file. This approach offers maximum compatibility, allows granular synchronization, and works reliably even with large address books.

Groups are per-contact categories
Groups are stored inside each contact as a category. This reduces the number of files but is less compatible with many clients and can cause sync issues.

Recommendation: For most setups, especially with multiple devices and external clients, “Separate vCards” is the safest and most reliable choice.

Server-side calendar invitations in Nextcloud

Nextcloud can send calendar invitations automatically via its mail backend when properly configured.

Setup steps:

  1. In the Admin Settings → Basic Settings → Email Server, configure a valid SMTP server (Nextcloud must be able to send mail).
  2. In Groupware → Calendar (CalDAV), enable Send invitations to attendees.
  3. Ensure each user’s email address in their personal settings matches a valid sender address.

Once active, invitations are sent server-side whenever an event with attendees is created — whether from the Nextcloud web calendar or a CalDAV client (e.g., DAVx⁵ with Samsung or Etar).
Responses (accept/decline) are processed automatically by Nextcloud.

Technical note:
Invitations are handled by the built-in SabreDAV iTIP/iMIP system, which generates and delivers .ics invites through the configured SMTP service.

Using DAVx⁵ Clients with F-Droid for Free

When setting up personal calendars and contacts via CalDAV and CardDAV, choosing the right client can make a big difference – not only for usability but also for privacy and cost. Many popular mobile apps either require a subscription or rely on proprietary services, which can compromise your control over your own data.

This is where F-Droid comes in. F-Droid is a free and open-source app repository for Android that hosts a wide range of applications, including DAVx⁵ clients, that respect user privacy. By using apps from F-Droid, you can synchronize your calendars and contacts without relying on cloud services that might track or monetize your data.

One major advantage of F-Droid is that it provides applications completely free of charge, and all the apps are open-source. This aligns perfectly with the principles of digital sovereignty, giving you full control over your data while avoiding hidden costs or forced subscriptions.

Installing DAVx⁵ from F-Droid

  1. Install F-Droid
    • Open your Android device and navigate to https://f-droid.org.
    • Download and install the F-Droid app. You may need to allow installation from unknown sources in your Android settings.
  2. Search for DAVx⁵
    • Open F-Droid, tap the search icon, and type DAVx⁵.
    • Select the app from the results and tap Install.
  3. Open DAVx⁵ and add account
    • Launch DAVx⁵.
    • Tap Add Account → Login with URL and User Name.
  4. Enter your server details
    • Server URL: cloud.examplecorp.io
    • Username: Your Nextcloud username.
    • Password: Your created app password.
    • Tap Login. DAVx⁵ will discover available calendars and contacts.
  5. Configure synchronization
    • Select which calendars and address books to sync.
    • Set sync frequency and notification preferences.
    • DAVx⁵ will now synchronize events and contacts with your Android device.

Notes and Tips

  • DAVx⁵ supports two-way synchronization, so changes on your device or server are mirrored automatically.
  • You can combine this with Thunderbird on desktop for a fully synchronized multi-device setup.
  • Since DAVx⁵ is open-source and hosted on F-Droid, there are no hidden costs or privacy compromises.

This setup provides a free, secure, and fully controllable environment for your self-hosted calendars and contacts, making it a solid alternative to commercial cloud services.

Using Thunderbird for Desktop

Thunderbird, paired with the Lightning calendar extension, provides a robust desktop solution for accessing your CalDAV calendars and CardDAV contacts hosted on Nextcloud. This allows you to manage your schedules and address books seamlessly alongside your email.

Installing and Configuring Thunderbird

  1. Install Thunderbird
  2. Enable Lightning Calendar (if not pre-installed)
    • Recent versions of Thunderbird include Lightning by default.
    • If missing, go to Tools → Add-ons → Extensions → Search Lightning → Install.
  3. Add a New Calendar
    • Go to File → New → Calendar → On the Network.
    • Choose CalDAV.
  4. Enter Details
    • Location/URL: https://cloud.examplecorp.io
    • Name: Choose a display name for the calendar (e.g., Personal, Birthday).
    • Color: Optional, for easier calendar differentiation.
    • Click Next and enter your Nextcloud username and password when prompted.
  5. Select Which Calendars to Sync
    • Thunderbird will list all available calendars from your NextCloud account.
    • Check the ones you want to synchronize.
  6. Test and Sync
    • Your events will now appear in Thunderbird.
    • Changes made in Thunderbird or on your server are synchronized automatically.

Notes and Tips

  • Thunderbird supports two-way synchronization with CalDAV, ensuring that updates on either side are mirrored.
  • You can combine this setup with DAVx⁵ on Android for full multi-device synchronization.
  • This approach keeps all data self-hosted and private, without relying on external cloud services.

Conclusion

Nextcloud provides a secure, self-hosted platform for calendar and contact management, built on the open-source SabreDAV framework. Using app passwords protects your main account while enabling seamless access for CalDAV/CardDAV clients. By exporting calendars from Google, importing them into Nextcloud, and sharing only with trusted users, you can maintain full control over your data while keeping synchronization smooth and secure.

Nextcloud combines the reliability of SabreDAV with a user-friendly interface, active community support, and ongoing security updates, making it a robust solution for personal or organizational calendar management.

References and Official Sources

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