Klassian Privacy Policy
Klassian is operated by Elkanah (sole proprietor: Kyujin Cho). Elkanah is the data controller for the processing described below.
1. What we collect, why, and on what legal basis
1.1 Account and profile — when you sign in
| Data | Purpose | Legal basis |
|---|---|---|
| Email, name (or nickname), social sign-in identifier | Identifying you, signing you in | Contract (Art. 6(1)(b)) |
| Display name | Showing who you are in groups you join | Contract |
| Instrument (only if you opt in) | Research and personalization | Consent (Art. 6(1)(a)) |
Sign in with Apple is currently the only sign-in method available. Google and Kakao sign-in are in preparation; when they become available, the data processed and the purpose remain as above.
Your display name is visible to members of groups you belong to, and changing it updates all of them.
1.2 Group collaboration — when you create or join a group
Group name, membership (role, display name), shared events (title, time, notes, venue), polls and votes, one-to-one lesson requests and comments.
- Purpose: providing shared scheduling. Legal basis: contract.
- Visibility: what you write is visible to members of that group (lesson requests and comments: only the two people involved). This is the feature working as designed, not a disclosure to third parties.
- While an invite link is valid, anyone holding it can see one thing before signing in: the group's name.
1.3 Notifications — if you allow them
Push token, platform, app version, language. Legal basis: contract.
Notification titles and bodies — including event titles and comment text you wrote — pass through Apple's push service (APNs), which may retain them for up to 24 hours for delivery. See §5 (International transfers).
1.4 Practice hand-off — while a practice session is running
While you practice, the session's state (score name, composer, elapsed time) passes through our server so your other devices (e.g., iPhone Lock Screen) can display it. It is deleted from the server when the session ends. Legal basis: contract.
1.5 Gaze improvement data — only with your separate consent, pseudonymous
- A pseudonymous install identifier (random UUID). It is not linked to your account or email, and we do not attempt to link it.
- Derived metrics only: calibration error, head and eye angles, distance from the screen, calibration and practice-game samples expressed as screen coordinates, page-turn success/attempts, dwell times, device model, OS version, TrueDepth availability, and gaze-related events (calibration started, page turned, recalibrated, and similar).
- If you also opted into instrument sharing: your instrument family (e.g., strings).
- What is never collected or transmitted: camera footage, photos, face images, individual frames, or any record of where you look while reading a score. All gaze computation happens on the device.
- Purpose: improving gaze-tracking accuracy and related research. Legal basis: consent, withdrawable at any time in Settings.
- Declining changes nothing — every feature, including gaze turning, works the same.
1.6 Usage analytics — only with your separate consent
Home screen usage and paywall interactions (paywall shown, plan comparison opened, purchase button tapped) — linked to your account, and deleted with it. It is stored and transmitted separately from gaze data (§1.5), and the two are never combined. Your scores, annotations, and playing are never part of it. Purpose: understanding which features are used and where friction occurs. Legal basis: consent. Declining changes nothing.
1.7 Payments — handled entirely by Apple
Purchases, renewals, and refunds are processed by Apple through the App Store. We never see your payment details, and we do not even store your subscription status on our servers — your device verifies it directly with Apple. If we grant you an access tier ourselves (beta testers, goodwill), only that grant is stored. Legal basis: contract.
1.8 Consent records
What you consented to, when, and in which app version — kept because the law requires us to be able to demonstrate consent (Art. 7(1)). Legal basis: legal obligation (Art. 6(1)(c)).
1.9 Marketing — only with your separate consent
Whether you opted into marketing messages. Declining has no effect on the service. Legal basis: consent.
1.10 Sign-up forms on our website — only if you submit one
- Launch updates: name, email address.
- Beta tester application: name, email address, affiliation, iPad model, whether you wear glasses or lenses, instrument, playing posture, practice frequency, score app you currently use, availability for the test and for an interview.
- Purpose: to send the launch announcement, and to select and contact beta testers.
- Legal basis: consent, given by submitting the form.
- Collected through Google Forms and Google Sheets — see §4 and §5.
This data is not linked to an app account, and is never combined with gaze improvement data (§1.5).
2. What stays on your device and in your own iCloud
The following never reaches our servers. It lives on your iPad and, if iCloud sync is on, in your own iCloud (your Apple account's private storage):
your score PDFs and covers · annotations, stamps, and text notes · your personal calendar including fees and settlement records · practice history · your gaze calibration state · library folders · group cover photos · app preferences (including sleep-alarm settings).
iCloud sync is on by default. Data in transit passes through Apple's servers but is stored in your private iCloud space, which we cannot access. You can turn sync off at any time in Settings → iCloud Sync, or exclude just your scores. Apple's privacy policy governs that storage.
Recordings of your playing never leave the device at all — they are excluded even from iCloud sync.
3. How long we keep things
| Data | Retention |
|---|---|
| Account, profile, group activity, notifications, consent records | Deleted immediately when you delete your account (except where law requires retention) |
| Live practice session state | Deleted when the session ends |
| Push tokens | Deleted on sign-out or when the token dies |
| Usage analytics | Deleted immediately when you delete your account — it is linked to the account |
| Gaze improvement data (pseudonymous) | For the life of the service. It is pseudonymised — we cannot single out whose it is — and the accumulated pool is what the accuracy of gaze tracking is built on. Because it is not linked to your account, it is unaffected by account deletion |
| Data on your device and in your iCloud (§2) | Until you delete it — we have no access |
| Launch-update sign-ups | Deleted once the launch announcement has been sent, or earlier on request |
| Beta tester applications | Deleted within 30 days of the end of that beta round |
4. Processors
| Processor | Role | Notes |
|---|---|---|
| Supabase, Inc. | Database, authentication, hosting | Servers are located in Seoul, Republic of Korea. The operator is a U.S. company; technical support may involve access from abroad. A standard data processing agreement (DPA) is in place |
| Apple Inc. | Push delivery (APNs), payments (App Store), sign-in | See §5 |
| Google LLC | Intake and storage of website sign-up forms (Google Forms, Google Sheets); sign-in | Form responses are stored on servers in the United States — see §5. Sign-in applies only once Google sign-in is offered, and only if you use it |
| Kakao Corp. | Sign-in | Applies only once Kakao sign-in is offered, and only if you use it. Processed in the Republic of Korea |
5. International transfers
Our servers are in the Republic of Korea. The European Commission has decided that Korea provides an adequate level of data protection (Decision of 17 December 2021, reconfirmed July 2026), and the United Kingdom has made the equivalent determination (Data Protection (Adequacy) (Republic of Korea) Regulations 2022). Your data may therefore be processed in Korea without any additional transfer safeguard.
When notifications are delivered, notification content (§1.3) is transferred to Apple Inc. (United States) for the sole purpose of delivery, retained for up to 24 hours. Apple is certified under and/or relies on recognised transfer mechanisms for its services; turning off notifications in iOS Settings stops this transfer entirely.
If you submit a sign-up form on our website (§1.10), the data you enter is transferred to Google LLC (United States), which hosts the form and the response sheet. Google relies on the EU Standard Contractual Clauses and the UK Addendum for such transfers. Not submitting a form avoids the transfer entirely; you can write to support@klassian.com instead.
Social sign-in and App Store payments may likewise involve those providers' servers abroad, under their own privacy policies. iCloud sync (§2) is a service between you and Apple.
6. Sharing
We do not sell personal data, share it for advertising, or disclose it to third parties, except where the law requires or you separately consent. There is no third-party analytics or advertising SDK in the app.
7. Gaze and camera — specific commitments
- The camera is used on the device only, to compute where you are looking. No footage, photo, or face image is ever stored or transmitted anywhere.
- We do not record where you look while reading. The only coordinates that leave the device are discrete calibration and practice-game samples — moments when the app asked you to look at a specific target — and only with your consent (§1.5).
- Gaze data is keyed to a pseudonymous identifier, stored in a separate server environment from account data, and it is our policy never to combine the two.
- For that reason, we cannot locate and delete any one person's gaze data — we cannot tell whose it is (see §8, Art. 11). What you can always do: withdraw consent in Settings, which stops collection instantly and discards anything still queued on the device.
8. Your rights
If you are in the EU/EEA or the UK, you have the right of access, rectification, erasure, restriction, portability, and objection (Art. 15–21 GDPR), and the right to withdraw consent at any time without affecting prior processing (Art. 7(3)). Most of this you can do directly in the app: edit or delete your profile, instrument, events, and scores; toggle each consent in Settings; delete your account in Settings.
- Data export: email support@klassian.com and we will provide your data.
- Account deletion removes your account, profile, group activity, notifications, usage analytics, and consent records from our servers immediately. Three things to know:
- Groups you own are deleted entirely — including shared events, polls, and comments that other members were using.
- Nothing on your device or in your iCloud is deleted — remove it yourself if you wish.
- Pseudonymous gaze data is not deleted, because it is not linked to your account (§7). Under Art. 11 GDPR, where a controller cannot identify the data subject, Articles 15–20 do not apply; we also do not collect extra information just to make identification possible.
- If you leave a group, what you wrote stays with the group, attributed to "a former member".
- You also have the right to lodge a complaint with a supervisory authority — in Korea, the Personal Information Protection Commission (privacy.go.kr); in the EU, your national data protection authority; in the UK, the ICO (ico.org.uk).
We do not use automated decision-making or profiling that produces legal or similarly significant effects (Art. 22).
9. Children
Klassian does not knowingly collect personal data from children under 14 (or the higher age applicable in your country, e.g., 16 where national law requires). Sign-up includes an age confirmation, and accounts cannot be created below the threshold.
10. Security
Encryption in transit (HTTPS) throughout; row-level security so that no query returns data beyond your own or your group's scope; identity data and gaze data kept in separate server projects with separate keys; session tokens in the device Keychain; no server admin keys in the app or repository; consent history stored append-only.
11. Changes
We will announce changes in the app and on the website at least 7 days before they take effect — 30 days for material changes such as new data categories or purposes.