Last updated: October 15, 2026
Carry the One ("the app") is a mental-math practice app for iPhone, iPad and Mac. This policy explains what happens to your data when you use it.
Carry the One does not collect, transmit, or sell any of your personal data. There is no account, no sign-in, and no server of ours. Everything the app knows about your progress stays on your device, and, if you keep iCloud sync on, in your own iCloud account, where only your devices can read it.
Carry the One stores the following on your device: in Apple's standard preference store (UserDefaults) and in files inside the app's own container:
None of this data is sent to us, to any server we operate, or to any third party. We have no backend and no analytics: the app doesn't make network requests to collect usage data. The one place it can go is your own iCloud, described below. Deleting the app removes all of it from that device. If iCloud sync was on, your iCloud copy remains until you delete it (see below).
Carry the One can keep your progress the same on every device signed in to your Apple ID: your iPhone, iPad and Mac. It is on by default and you can turn it off at any time in Settings › iCloud sync.
When it is on, the app stores a copy of your progress (skills, statistics, streaks, answer history and the mistake patterns derived from it, classes, review sets and saved sets, and your onboarding answers including your first name) in the private database of your own iCloud account, using Apple's CloudKit. That storage belongs to you: it counts against your iCloud quota, Apple's iCloud terms govern it, and it can be read only by your devices. We have no access to it and cannot see what is in it. Appearance, keyboard and reminder settings are not synced.
To remove the copy, use Settings › iCloud sync › Delete iCloud copy on any device; this deletes it from iCloud and turns sync off on that device. What is on each device stays on that device until you delete the app there. If you never sign in to iCloud, or turn sync off, nothing leaves the device.
Carry the One can turn one of your review sets into a short code beginning FCSET1-, which you can send to someone else however you like. The code travels through whichever app you choose to send it with. It does not pass through us. It contains only the set's own contents: which skills it covers, its target date, and its name. It carries no personal information and no statistics.
Carry the One offers an optional auto-renewing subscription ("Carry the One Pro"), handled entirely through Apple's In-App Purchase (StoreKit) system. Payment information and transaction history are processed and stored by Apple, governed by Apple's Privacy Policy. We never see or store your payment details.