Privacy Policy
Cairn · Last updated: October 2026
Cairn is a habit tracker designed to work without knowing who you are. This page explains what we store and why.
What we collect
- Anonymous account. A random ID, the cryptographic hash of your sync token, and the hash of your recovery code. We never store the token or the recovery code themselves.
- Synced data. If you turn on cloud backup, your habits, categories, preferences and completion records are stored so your data can follow you across devices. In privacy backup mode, titles and notes stay on your device — only the numbers are synced.
- Device information. Platform (iOS or Android), app version, and last sync time.
- Operational logs. Route, status code and request ID, used only for reliability and capacity work. We never log your content, token or recovery code.
What we never collect
No analytics, no trackers, no advertising identifiers, no name, email or phone number. We do not sell or share data — we have nothing that could identify you.
Where data lives
Synced data is stored in Cloudflare databases in the region serving your requests.
How long we keep it
Until you delete your account in the app. Anonymous accounts that never synced any data are removed automatically after 90 days of inactivity.
Your choices
- Turn cloud backup on or off at any time in Settings.
- Export your data as CSV at any time, free of charge.
- Delete your account and all synced data in Settings → Account. You can also contact us with your recovery code and we will delete it for you.