Privacy Policy

Cairn · Effective 10 October 2026 · Last updated 13 October 2026

Cairn is a savings planner. You tell it what you're saving for and what your bank says, and it tells you what a purchase costs in time. This policy explains what the app does with your information.

1. Your plan

Cairn stores the following on your device, inside the app's own storage:

• Your balance — a number you type, or read off a screenshot you share (section 3).
• Your pots — what you're saving for, what each costs, what it holds and when it's due.
• Your emergency fund, what comes in each month, what you pay, any repayments and anything you invest.
• The record of your check-ins, and the things you decided to buy or not to buy.
• Spending you add — each purchase's amount, date and category, typed in or read from a statement or screenshot you choose (section 3). For a purchase read from your bank, Cairn keeps the bank's name for it with any card or reference number taken out, a short fingerprint (date, amount and shop) so the same statement read twice isn't counted twice, and the category you picked for each shop so it is sorted for you next time.

None of this is transmitted anywhere. Cairn does not connect to your bank, and we run no server that could receive it. It is never used for advertising and never sold.

2. Photos

If you put a picture on a pot, Cairn asks to pick a photo, copies that one photo into its own storage on your device, and never reads the rest of your library. If you pick a screenshot of your bank app instead, it is read as described in section 3 and not kept.

3. Reading a screenshot or a statement

If you share a screenshot of your bank app into Cairn, or pick one at a check-in, the balance is read off it on your phone using Apple's own text recognition. The screenshot is deleted as soon as that is done. Nothing about it leaves your phone, and Cairn keeps neither the picture nor anything on it except the number you confirm.

If you add spending from a bank statement (a PDF or CSV file) or a screenshot of your bank's list of purchases, the file is read on your phone and deleted as soon as it has been read. Nothing in it leaves your phone. You see every purchase before anything is kept, and Cairn keeps only the purchases you log, as described in section 1, so that any one of them can be taken off again. It keeps nothing else from the file: not your balance, not money coming in, not the purchases you leave out, and not your account or card numbers.

4. What leaves your device

Only subscription information.

Cairn is paid for with an App Store subscription. Apple processes the payment; Cairn never sees your name, your Apple ID, your card or your billing address.

To know whether your subscription is active, Cairn uses RevenueCat. When you subscribe, restore a purchase or open the app, RevenueCat receives:

• an anonymous identifier, a random string created on your phone. It is not your Apple ID or your device's hardware identifier, and it is not linked to your name, email or any account;
• your purchase history in Cairn — which plan, when it started, whether a trial is running, and when it renews or ends;
• basic technical information their SDK collects, such as device model, operating system version, app version, region and IP address.

RevenueCat receives nothing about your plan: no balance, no pots, no check-ins. We use this only to know whether Cairn should be open for you.

RevenueCat's privacy policy: revenuecat.com/privacy
Apple's privacy policy: apple.com/legal/privacy

5. Sharing a link into Cairn

If you share a product link into Cairn from another app, Cairn fetches that page, from your phone, to read the product's name and price so you don't have to type them. That request goes to the website you shared, exactly as it would if you opened the link in Safari. Cairn sends nothing else with it and keeps nothing from the page but the name and the price.

Sharing from Safari itself doesn't need even that: the price is read from the page already open.

Apart from this and section 4, Cairn contains no analytics SDK, no advertising SDK, no crash reporting and no social media integrations.

6. Reminders and the widget

If you turn on check-in reminders, they are scheduled locally on your device. Cairn has no push notification server and never registers a push token.

A lock screen can be read by anyone holding your phone, so reminders and the lock-screen widget name a pot and the month it lands in, and never an amount. You can turn reminders off in Cairn's Settings, or in the iOS Settings app.

7. Backups

Because your plan lives in the app's storage, it is included in your device's own iCloud or computer backup if you have that turned on.

You can also save a backup yourself from Cairn's Settings. Cairn writes your plan and its photos into a file and hands it to the iOS share sheet; where it goes from there is your choice. The file is not encrypted — it is a plain record of your money — so keep it somewhere private. Cairn never makes a backup on its own or sends one anywhere.

8. Sharing a receipt

If you share a receipt of your decisions, Cairn draws an image and hands it to the iOS share sheet. Where it goes from there is your choice. "Hide my balances" leaves your figures off it.

9. This website

The app talks to no server of ours, but these pages have to be served from somewhere. mutterware.com is hosted on Netlify. Like any web host, Netlify processes standard request information when you load a page — your IP address, browser and operating system, the page requested, and the time of the request — in order to serve the site and keep it secure. That happens when you visit this website, and is separate from anything the app does.

We add no analytics, tracking pixels, advertising tags, or cookies to these pages, and nothing here is linked to your app data.

Netlify's privacy policy: netlify.com/privacy

10. Children

Cairn is not directed at children under 13, and we do not knowingly collect personal information from them. The app has no accounts and asks for no email address or date of birth, and we hold no plan data on any server of ours. The exception is the subscription record described in section 4. If you believe a child has subscribed through the app, contact us at the address below and we will act on it.

11. Deleting your data

Because your plan is stored only on your device, deleting the app removes all of it — your pots, your history, your spending and your settings — unless you saved a backup file yourself. "Start over with a new plan" in Cairn's Settings erases the plan without deleting the app. Any purchase you logged can be taken off on its own from its category on the Spending tab, and a whole month can be cleared there too.

Subscription records held by RevenueCat and Apple are separate from this, and are retained under their own policies. To request deletion of the record associated with your anonymous identifier, contact us at the address below and we will pass the request on.

12. Your rights

Depending on where you live, you may have rights to access, correct, export, or delete personal information held about you — including under the Australian Privacy Act 1988 (Cth), the EU/UK GDPR, and the California Consumer Privacy Act.

In Cairn's case, the practical answer to most of these is the same: your plan is already in your sole possession on your device, and deleting the app deletes it. We hold no server-side profile of you to produce, correct, or erase. For the subscription record described in section 4, contact us and we will act on your request.

Cairn does not sell personal information, and does not share it for cross-context behavioural advertising.

13. Changes to this policy

If this policy changes materially, the updated version will be posted here with a new "last updated" date. Continuing to use the app after a change means you accept the revised policy.

14. Contact

Mutterware — an independent software business operating from Victoria, Australia.

Email: studio@mutterware.com
Our full legal and contact details are available on request by email.