Privacy Policy

Last updated November 1, 2026

Cairn - Metrics ("Cairn") shows live system stats for your Macs on your Mac, iPhone and iPad. This policy explains what the app does with your data. In short: your data stays in your own iCloud, and we never receive it.

What Cairn collects

On a Mac, unless you turn off "Collect This Mac's Stats" in Settings, Cairn reads CPU, memory, disk, battery, network and uptime from the Mac's standard system APIs, plus the Mac's name, model, chip, macOS version, serial number, IP address and startup disk name. It saves these, and a history of them, to your iCloud account. The iPhone and iPad apps only display computers; they don't publish anything.

By default a small background item, Cairn Helper, starts when you log in and keeps collecting after you close Cairn. It runs only on your Mac, and saves to your iCloud account the same as the app does. In Settings, "Keep Collecting When Closed" can change it to a menu bar icon, or to nothing running when Cairn is closed.

Where it is stored

Everything is stored in the private CloudKit database of your own iCloud account, using the iCloud storage you already have. We run no servers and have no access to it. A copy of the last list of computers is kept on your device so the app opens with data on screen.

Who can see it

Only you, and anyone you choose to share a computer with. If you share a computer, the person you invite can see that computer's stats, history, name and hardware model. Its serial number, IP address and startup disk name stay hidden from them unless you turn each one on for that computer on its Sharing screen. Your own devices always see them. People you invite see only the computers you share with them, you can see who a computer is shared with, and you can stop sharing with anyone at any time.

What we don't do

• No account to create.
• No analytics, advertising or tracking, and no third-party SDKs.
• No data sent to us or to third parties.
• The app asks for no system permissions.

Deleting your data

Turn off "Collect This Mac's Stats" to stop a Mac publishing. Removing a computer from Cairn deletes its records from your iCloud account, including its history, and removing this Mac's own computer also turns collecting off. "Keep history for" in Settings sets how much history is kept, from one hour to a week, and shortening it deletes older history from iCloud. You can also manage or delete the app's iCloud data in Settings > Apple Account > iCloud > Manage Account Storage.

Children

Cairn does not collect personal information from anyone, including children.

Changes

If this policy changes, the new version will be posted here with a new date.

Contact

Questions about privacy? Email developer@startoni.com, or see the support page.