Cairn · Last updated 8 October 2026
Cairn is made and operated by Opia Prosper, an independent developer ("we", "us"). For anything in this policy, contact us at kopixxsoftware@gmail.com.
Cairn deliberately has no sign-up, no sign-in and no user accounts. We do not collect your name, email address, phone number, date of birth, photograph or any social media identity.
Instead, when you first open the app it generates a random identifier (a UUID) and stores it on your device. That identifier is how our server recognises requests from your copy of the app. It is not derived from your device's hardware identifiers, your advertising ID, or anything about you, and it is not shared with anyone except as described in section 5.
Because identity follows the device, a new phone or a reinstall is a new, empty Cairn. Your recovery history does not transfer. Your subscription does, via Restore Purchases, because Apple tracks that against your Apple ID.
Only what the app needs to work:
We do not collect your location, contacts, photos, microphone, camera, Apple Health data, browsing history, or any list of sites you have visited. Cairn does not monitor, filter or block anything on your device.
Journal entries and coach messages are encrypted with AES-256-GCM before they are written to our database, and decrypted only to serve them back to your device. Everything travels over HTTPS.
To be straight with you about the limits of that: we hold the encryption key on our server, because the app has no account and therefore no password from which a key could be derived. This protects your writing against database theft and against casual access. It is not end-to-end encryption, and we are not going to describe it as though it were.
The mood, energy and urge-level answers you give in check-ins are wellbeing information, and are stored against your random install identifier as described above.
We do not sell your data. We do not share it for advertising. Ever.
Four processors are involved in running the app:
Our servers are hosted by WebHostingBliss, in Canada (Quebec). That means anything the app sends us is stored in Canada, wherever you are. We will disclose data if we are legally compelled to; given what we hold and what we do not, there is very little to disclose.
Until you delete it. You can erase everything yourself, instantly, from inside the app (section 7). We do not currently delete inactive records automatically; if we ever introduce that, we will say so here and in the app first.
Open Settings → Erase my data in the app. This permanently deletes your stones, check-ins, relapses, journal entries, missions, plan, coach messages and emergency sessions from our servers, along with the device record itself. It is immediate and it cannot be undone.
Erasing your data does not cancel your subscription — Apple bills that, and you cancel it in Settings → your name → Subscriptions on your iPhone. It also does not remove purchase records held by Apple and by RevenueCat, which keep those under their own policies; to ask RevenueCat to delete its record, email us the install identifier and we will pass the request on.
Depending on where you live, you may have rights to access, correct, export, restrict or delete your data, and to object to its processing. The app's own erase function covers deletion instantly. For anything else, write to kopixxsoftware@gmail.com.
Because there is no account, we cannot verify who you are from an email alone. To act on a request about a specific device's data we will need the install identifier, which you can find in Settings → About Cairn.
Cairn is rated 17+ and is not for anyone under 18. We do not knowingly collect data from children.
Cairn is a self-help tool. It is not therapy, not a medical device, and not a substitute for professional treatment. Nothing in it is a diagnosis. If you are in crisis, the app's crisis resources are available without any subscription or account at all.
If we change this policy materially, we will say so in the app before the change takes effect. The date at the top always reflects the current version.