CDC
Two surfaces, two different data practices. The web app collects nothing. The mobile apps offer an optional Pro tier with opt-in, end-to-end-encrypted cloud sync.

Privacy

Two surfaces, two different data practices.

Web (citizenshipdaycalculator.com)

All calculations happen in your browser. We do not run analytics. We do not set cookies beyond the cookie required for your chosen language. We do not have an account system. No data leaves your device.

Mobile apps (iOS + Android)

The free tier behaves identically to the web — fully offline, no account, no data leaves your device. The optional Pro tier introduces:

  • Account creation via Sign in with Apple, Sign in with Google, or email magic link
  • Cloud sync — your trip data is encrypted on your device with AES-256-GCM before being sent to our server at api.citizenshipdaycalculator.com; we never see the plaintext
  • Anonymized crash reports (Sentry), toggleable from Settings → Privacy. Product analytics is not active in this build.
  • Push notifications for eligibility reminders

You can use the mobile app forever on the free tier without any of these server-side features.

  • Web: No account creation is required. The web app at citizenshipdaycalculator.com is 100% client-side.
  • Mobile free tier: behaves identically to the web — no account, no data leaves your device.
  • Mobile Pro (opt-in): trip data is encrypted on the device with AES-256-GCM before any sync; the server only ever stores ciphertext bound to your user ID and the country slug.
  • JSON backup/restore and PDF generation happen entirely on your device — no file is sent to any server.
  • Web has no usage analytics, no cookie-based tracking, and no third-party trackers.
  • Mobile Pro: anonymized crash reports (Sentry) are off by default and can be toggled in Settings → Privacy. Product analytics is not active in this build.
  • If you opt-in to AI features (where available), your Anthropic API key is stored locally; requests go directly from your device to Anthropic.
  • Cloud-sync server (mobile Pro only) keeps basic server logs (IP, date) for technical purposes only.