Piano Class is an app for piano teachers and their students, most of whom are children. This policy says what we store, why, for how long, who it is shared with and what rights you have. It is short and concrete so a parent can read it in five minutes.
Who we areWho this coversWhat we storeWhat we do not collectWhat it is used forWho it is shared withChildrenHow longYour rightsSecurityChangesContact
1Who we are
Piano Class is the app for iPhone and Android and the website at pianoclass.app, operated by Huy Ly ("we"). Email: hotro@pianoclass.app.
2Who this policy covers
- Teachers: adults who sign in with a Google or Apple account, create classes and manage their own students.
- Students: usually children. A student account is created by a parent or a teacher; the child only types a PIN to play. Each student belongs to exactly one teacher, and that teacher is the first person a parent talks to about the child's data.
- Visitors of the website: the public pages set no cookies and run no analytics.
3What we store
The table lists exactly what the system keeps, and nothing more.
| About whom | Data | Where from |
|---|---|---|
| Teacher | Name and email from Google or Apple, the identifier the sign-in provider issues (never a password), the chosen note-name style. | Sign-in, settings |
| Class | Class name, description, colour, class logo (if uploaded), join code. | Created by the teacher |
| Student | Username, display name, a short note (for example "Grade 3"), a portrait photo if the teacher uploaded one, waiting or approved status. The PIN is stored only as a one-way hash; we cannot read it. | Created by a parent or the teacher |
| Attempts | The assigned exercise, every answer, right or wrong, the time taken per note, the score, when it started and ended, the number of attempts. | The student playing |
| The teacher's content | Questions, tests, uploaded illustrations. | Written by the teacher |
| Session | A session token (random, stored hashed) so the device does not sign in again every time the app opens. | The app |
| Safety log | For every sign-in or join request: the IP address, the time, success or failure. Used to lock after 5 wrong PINs. The server log records only the path, the status code and the duration, never what was sent. | The server |
4What we do not collect
- No advertising, no advertising identifiers.
- No third-party analytics or crash-reporting kit.
- No location, contacts, microphone or photo library (a picture is sent only when a teacher picks or takes one as a class logo, as a student's photo or as a question illustration).
- No tracking across other apps or sites.
- No email, phone number or date of birth of a student.
5What we use the data for
- Running the class: signing in, showing exercises to students, showing results to the teacher.
- Keeping the service safe: limiting PIN attempts, rate limiting, spotting abuse.
- Answering when you contact support.
We do not profile behaviour, do not sell data and do not use it for marketing.
6Who the data is shared with
- Google and Apple, only when a teacher signs in. They confirm the teacher's identity and send us a name, an email and an identifier. Their side is governed by their own policies.
- The hosting provider: a rented server outside Vietnam that we administer ourselves. The data and its backups live on that server.
- Where pictures are kept: Cloudflare (its R2 storage and content delivery network). Class logos, student photos and question pictures live there, at random addresses nobody can list, after our server has stripped every bit of information a picture file carries with it (where it was taken, for example). Removing a picture in the app removes it there.
Because the server is outside Vietnam, personal data is transferred abroad for storage and processing. We carry out this transfer under the Law on Personal Data Protection and Decree 356/2025/NĐ-CP.
Beyond those, nobody else receives the data unless the law requires it.
7Children
- A student account is created by a parent or a teacher, after a class code from the teacher. A child cannot sign up alone.
- We do not ask a child for a real name, an email, a phone number or a date of birth. The display name is chosen by the parent and may be a nickname.
- The teacher of the class sees the child's results. Nobody else does.
- A child's photo, if there is one, is taken or chosen by the teacher and only with the parent's consent. It is shown only to the child, the parent and the teacher of the class, stored at a random address nobody can list, and deleted with the account. A parent can ask the teacher to remove it at any time.
- A parent can ask the teacher to correct or delete the child's account, delete it in the app, or write to us. If you believe an account was created without a parent's consent, tell us and it is removed.
8How long we keep it
| Data | Retention |
|---|---|
| Accounts, classes, attempts, content | Until the account is deleted. Deletion removes the rows at once; there is no "trash". |
| Backups | 14 days. A deleted record can survive in a backup for up to 14 days and is never restored on its own. |
| Sessions | Expire after 60 days without use; signing out revokes them at once. |
| Safety log (IP, PIN attempts) | 30 days. |
| Server log | 14 days. |
9Your rights
Under the Law on Personal Data Protection (Law No. 91/2025/QH15) you have the right to know, access, correct, delete, withdraw consent and receive a copy of your data. For a child's data, a parent exercises these rights on the child's behalf.
- Access and correction: a student's display name, note and photo are edited or removed by the teacher; a teacher edits their own name and settings in the app.
- Deletion: in the app, open Settings and choose Delete account. See how to delete an account.
- A copy of your data and other requests: email us from the email you sign in with (teachers) or through the teacher of the class (students). We answer within 30 days.
10Security
- Every connection is encrypted (HTTPS).
- PINs are hashed with scrypt; session tokens are hashed before they are stored.
- Each teacher's data is isolated at the database level: one teacher cannot read another's data even on purpose.
- A 15-minute lock after 5 wrong PINs; rate limits per address.
- Nightly backups, kept for 14 days.
No system is perfectly safe. If an incident affects your data, we notify the teachers concerned by email within 72 hours of confirming it.
11Changes to this policy
When the policy changes we update the date at the top and, for a significant change, notify teachers in the app before it takes effect.
12Contact
Any question about data goes to hotro@pianoclass.app.