Kalender Sync MCP ServerVerifiedFeatured

Calendars and syncs for your AI assistant

Kalender Sync connects Google Calendar, Microsoft 365/Outlook, Apple iCloud and CalDAV calendars through one EU-hosted remote MCP server. Supported CalDAV services include GMX, WEB.DE, mailbox.org, Posteo, STRATO and kSuite. iCal feeds provide read-only access.

What you can do

• Check availability across calendars and search for events.
• Create, update and delete events, including individual occurrences of recurring events, subject to provider support and the permissions you grant.
• Respond to invitations where the provider supports scheduling. iCloud supports responses to invitations from iCloud organizers; invitations from external organizers such as Google or Outlook cannot be answered through iCloud. CalDAV invitation responses require scheduling support; response comments are not transmitted.
• List and diagnose calendar syncs, preview a new sync, create it after confirmation, pause or resume it, and preview and confirm deletion.

Connect securely

Endpoint: https://app.kalender-sync.de/mcp — Streamable HTTP.

For clients other than Claude and ChatGPT, use a personal access key. In Kalender Sync, open AI assistant → Connect the assistant → Something else, select the calendars and permissions, and choose Create key. Store the key locally and send it as the HTTP header Authorization: Bearer ksa_…. Never paste a key into a chat or a public configuration. The configuration on this page uses an environment-variable placeholder; use your client's supported secret storage or substitution syntax.

OAuth sign-in is available for Claude and ChatGPT. Other clients use the access-key method above.

You control which calendars the assistant sees, the detail level, and its permissions to create events, manage existing events and manage syncs. Existing-event management requires full details and the corresponding permission. Sync changes require permission on the target calendar. Syncs keep running if assistant access is revoked; pause or delete the sync separately when needed.

15 tools

list_calendars, get_availability, search_events, create_event, update_event, delete_event, respond_to_event, send_feedback, list_syncs, diagnose_sync, preview_sync, create_sync, set_sync_paused, preview_delete_sync, delete_sync.

Get started

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App screenshots

Calendar sync and sharing setup in the Kalender Sync app. Sharing with other people is configured in the app.