Chunja

Effective: 2026-09-03 — iOS bundle ID: kr.nikkm.highMrD — Android package: com.ootssu.chunja

Short version

Chunja is a study app for the 千字文 (Thousand Character Classic). The study content ships inside the app and your learning progress never leaves your device. There are no user accounts, no sign-up, and no advertising or analytics SDKs. There is one exception to "nothing leaves the device": if you choose to buy Chunja Pro, purchase information is processed by our payments provider — see In-app purchases below.

What stays on your device

• Your learning progress — which stanzas you have studied, which characters you have marked as known, and the schedule for spaced-repetition reviews. This is saved in the app's own private storage on your device (the Application Support folder on iOS, app-private files on Android) and never leaves your device.
• Your display preferences — reading language (Korean / English / Japanese) and other UI options. Saved in this app's private settings storage (UserDefaults on iOS, SharedPreferences on Android).

If you delete Chunja from your device, all of the above is removed.

Network requests

The app makes one optional, anonymous network call: to display a small recommendation card for other apps from the same developer, the app fetches a public list of app names and icons. This request does not identify you and we do not record IP addresses on our side. The card never appears outside the Settings tab.

The bundled study content (1,000 characters and 250 stanzas of the 千字文) is included inside the app at install time and does not require a network connection to read.

In-app purchases

Chunja Pro (test mode and the mistakes notebook) is an optional one-time purchase — not a subscription. Reading all 250 stanzas, spaced-repetition review and tracing are free.

If you buy it, the payment itself is handled entirely by the app store (Apple App Store or Google Play). We never see your name, email address, or card details. To know whether the purchase is active, the app uses RevenueCat as our payments provider. RevenueCat receives the store receipt and an anonymous installation identifier that it generates on your device, and answers whether Pro is unlocked.

That identifier is not tied to a name or an account. But because it identifies an installation, we treat it as personal data rather than calling it anonymous. It is used only to unlock what you paid for and to let you restore the purchase later; restoring uses your store account, not any profile we keep. Data in transit is encrypted.

To be precise about when this happens: the app asks our payments provider each time it comes to the foreground whether this installation has an active purchase, even if you have never bought anything. That check sends the anonymous installation identifier and nothing else, and it is what lets a purchase be restored on a new device. If you never buy, the answer is always "no purchase" and no purchase record is created for you.

To have a purchase record deleted, email the address at the bottom of this page.

What we do not do

• No accounts. No sign-up. No login.
• No advertising identifiers, no tracking SDKs, no analytics SDKs.
• No cross-app tracking; no use of NSPrivacyTrackingDomains.
• No access to contacts, photos, camera, microphone, location, or health data.
• No third-party AI service receives anything from your device.

Children

Chunja is intended for general audiences interested in classical East-Asian literacy. The app has no accounts and asks nothing about you. The only record that leaves the device is the purchase record described above, and that exists only if someone buys Chunja Pro — we do not profile users of any age, and we do not knowingly build any profile of a child.

Changes to this policy

If we ever change this policy, the new version will be posted at this URL with an updated effective date.