Calendar Busy Sync — Privacy Policy

Overview

Calendar Busy Sync is a Chrome extension that mirrors events between two Google Calendars the user selects, creating private "Busy" placeholders so free/busy lookups stay accurate across both calendars. The extension runs entirely inside the user's browser. There is no backend server, no analytics, and no third-party data sharing. This policy explains what the extension touches and what it deliberately does not.

What data the extension accesses

• Google Calendar event data (titles, times, attendees, transparency) — only on the two calendars the user explicitly selects, and only via the user's own OAuth grant.
• The user's Google account identity, returned as part of the OAuth sign-in flow handled by Chrome.
• Extension settings the user enters: selected calendar IDs, sync interval, auto-sync on/off, and a record of the last sync attempt.

How the data is used

• Reading events from the source calendar within a configurable time window (default: 1 day back, 60 days forward).
• Creating, updating, and deleting "Busy" placeholder events in the target calendar to mirror the source. Placeholders are tagged with private extended properties so they can be safely managed across runs without affecting unrelated events.
• Persisting the user's chosen configuration so the extension can resume on Chrome restart.

What data is NOT collected or transmitted

• No backend server operated by the developer. The extension does not POST data anywhere except Google's Calendar API.
• No analytics, no telemetry, no error reporting services.
• No third-party SDKs, trackers, or advertising.
• The developer has no ability to read any user's calendar data.

Where data is stored

• Configuration: in chrome.storage.sync and chrome.storage.local, which live inside Chrome and (for sync) the user's Google account.
• OAuth access token: managed by Chrome via chrome.identity. The token is never exposed to or read by the developer.
• Calendar events: in the user's Google account, exactly as before — the extension only reads and writes via Google's API.

Sharing with third parties

None. The only network party the extension talks to is Google's Calendar API, on the user's own authorization. No data is sold, transferred, or otherwise made available to anyone else.

Limited Use

Calendar Busy Sync's use and transfer of information received from Google APIs to any other app will adhere to the Google API Services User Data Policy, including the Limited Use requirements. The extension only uses Google Calendar data to provide the calendar busy-sync feature visible to the user; it does not transfer this data to others except as necessary to provide that feature; it does not use the data for advertising; and no humans read the data except with the user's explicit consent, to comply with applicable law, or for security purposes. No Google user data is used to train generalized AI or ML models.

User controls

• Revoke the extension's access at any time at https://myaccount.google.com/permissions.
• Inside the extension popup: Sign out revokes the cached token; Remove placeholders deletes every placeholder the extension created; Reset extension does both and clears all local configuration.
• Uninstalling the extension removes its local storage. Placeholders previously created remain in Google Calendar until removed via Remove placeholders before uninstall (or manually in Google Calendar).

Children's privacy

The extension is not directed at children under 13 and does not knowingly collect data from them.

Changes to this policy

Material changes will be reflected on this page along with an updated "Last updated" date. Continued use of the extension after a change constitutes acceptance of the revised policy.

Contact

Questions: hello@antonkrokhmal.com