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Privacy Policy

Last updated: May 2026

Overview

Circadianly is built with privacy as a core principle. The extension's core features operate entirely on your device. Two additional capabilities involve external services: an optional AI-powered calendar feature that sends your calendar events to an AI model, and background usage analytics that collect anonymous interaction data. This policy explains exactly what is collected, by whom, and why.

What we collect

Core extension

Your wake-up time and preferences are stored locally using the Chrome Storage API and never leave your device.

Google Calendar integration (optional)

If you connect Google Calendar, Circadianly reads your calendar events — including event titles, times, descriptions, and attendee information — and processes them entirely on your device using Chrome's built-in AI (Gemini Nano) to generate personalised phase advice. No calendar data is transmitted to external AI servers. You can revoke access at any time from the extension settings or from your Google Account permissions page.

Usage analytics

Circadianly uses PostHog to collect anonymous usage data — which features you interact with and how you use the extension. Each installation is assigned a random identifier that is not linked to your name, email address, or Google account. We use this data solely to understand how the extension is used and to improve it. Opt-out controls are planned for a future version.

Local storage

The extension stores the following data locally on your device:

  • Your wake-up time (used to compute the five circadian phase windows)
  • Extension preferences and settings
  • Google OAuth token (only if you connect Google Calendar; used to authenticate requests)

None of this data is transmitted anywhere except as described above.

Permissions

Circadianly requests the following browser permissions:

  • storage — saves your local preferences and wake time between sessions
  • identity — authenticates with Google when you enable the Calendar integration
  • https://www.googleapis.com/auth/calendar.readonly — grants read-only access to your Google Calendar events, requested only when you enable the Calendar integration

Third-party services

  • Google Calendar API — provides read-only access to your calendar events when the integration is enabled. Calendar data is processed on-device and is not shared with Google for AI purposes.
  • Chrome Built-in AI (Gemini Nano) — an on-device AI model built into Chrome that processes your calendar events locally to generate phase advice. No data leaves your device during inference.
  • PostHog — collects anonymous usage analytics identified only by a random device ID.

Your choices

  • Google Calendar: you can disconnect at any time from the extension settings, which removes the stored OAuth token and stops any calendar data from being sent.
  • Analytics: opt-out controls are planned for a future version of the extension.

Children's privacy

Circadianly is not directed at children under 13. The Google Calendar integration accesses personal calendar data and should not be used by children under 13.

Changes to this policy

If we make material changes to this policy, we will update the date at the top of this page and release a new version of the extension.

Contact

Questions? Reach us at mail@yahht.com.