All your calendars. One place.
Work on Google? Family calendar on Nextcloud? Personal plans stored locally? See them together without changing how you do things.
Clockenstein
A focused desktop calendar for local events, Google Calendar and CalDAV. Open source, cross-desktop and made to feel at home on Linux.
Your calendar, your way
Work on Google? Family calendar on Nextcloud? Personal plans stored locally? See them together without changing how you do things.
Get on with your day. Clockenstein keeps an eye on what’s coming and lets you know when it’s time.
Your local calendars always work, and synchronized events remain available when the connection disappears.
Clockenstein is developed by the XApp Project. It does not use advertising, analytics or tracking, and the XApp Project does not operate a server that receives your calendar data.
Clockenstein processes the information needed to provide its calendar features:
Google access is limited to viewing the calendars in your calendar list and viewing, creating, changing and deleting calendar events. Clockenstein uses this access only to display, synchronize and manage calendars and to provide event reminders that you request.
Calendar settings and a synchronized event cache are stored in ~/.local/share/clockenstein on your computer. Google OAuth credentials are stored locally. CalDAV passwords are stored in your desktop’s secure keyring through Secret Service. Clockenstein communicates with Google and CalDAV services over the connections provided by those services.
You are responsible for securing your Linux user account and device. No method of storage or transmission is guaranteed to be completely secure.
The XApp Project does not receive, sell, rent or use your calendar or account information for advertising. Clockenstein sends calendar information only to the provider you choose when necessary to synchronize or perform an action such as creating, editing or deleting an event. Your provider processes that information under its own terms and privacy policy.
Clockenstein keeps synchronized calendar data locally while the corresponding account remains connected. Removing an account from Clockenstein deletes its locally stored account record, cached events and Clockenstein-managed credentials. Credentials supplied through GNOME Online Accounts remain managed by that service.
You can remove an account from Clockenstein’s account settings. You can also revoke Google access from your Google Account’s third-party connections page. To remove all remaining local Clockenstein data, uninstall the application and delete ~/.local/share/clockenstein. Deleting local data does not delete events held by Google or a CalDAV provider; manage those with the provider directly.
Clockenstein’s use and transfer of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements. Google user data is used only to provide and improve user-facing calendar functionality, is not used for advertising, and is not transferred to third parties except as necessary for security, legal compliance, or with the user’s affirmative consent.
Clockenstein is a general-purpose calendar and is not directed to children. The XApp Project does not knowingly collect personal information from children through Clockenstein.
This policy may be updated when Clockenstein’s features or data practices change. The revision date above will identify the latest version.
For privacy questions, requests or concerns, contact the XApp Project through the Clockenstein issue tracker. Please do not include private calendar information or credentials in a public issue.
Legal
Last updated: 25 August 2026
Clockenstein is provided by the XApp Project under the GNU General Public License version 3. Your use, copying, modification and distribution of the software are governed by that license.
You retain ownership of your calendar content. You authorize Clockenstein to access and modify data with a connected provider only when needed to provide features you choose. You are responsible for your provider accounts and for complying with their terms.
Clockenstein is provided “as is”, without warranty, to the extent permitted by applicable law. Always keep appropriate backups of important calendar data. The project does not guarantee uninterrupted synchronization, reminder delivery or compatibility with every provider.
Do not use Clockenstein to violate applicable law, interfere with services, bypass access controls or access calendar data without authorization.