Mathsight — Privacy Policy

Last updated: October 3, 2026

Mathsight is operated by Guangzhou Pashanhu Intelligent Information Co., Ltd. ("we", "us"), Room C7657, 6/F-7/F, Block I, No.6 Helong 1st Heng Road, Hebian, Baiyun District, Guangzhou, Guangdong 510440, China.

Mathsight is a math video learning service for students in Grades 1 through 12. We collect the minimum amount of data necessary, and what we collect depends on the age setting described below.

The age step

When the app first starts, we ask for the user's birth year and month to determine whether the user is under 13 or 13 and older. This happens entirely on your device: the birth year and month — and the resulting age setting — are not uploaded to us. We ask for this information solely to comply with children's privacy laws, including COPPA. The age setting can be changed later in the Grown-ups area of the app (a parental check applies).

What we collect

For all users:

• Subscription status and transaction identifiers (provided by Apple / Google): used only to verify and renew subscriptions, and to detect refunds — they contain no payment information. Payments are processed entirely by the App Store / Google Play; we never see or store your payment details.
• An anonymous account identifier: a random value used to operate the service — creating and authenticating the account, validating the subscription, and delivering content (including video playback authorization). It contains no name, email address, or other directly identifying information.
• Server logs (including IP address): like most online services, our servers automatically receive technical information such as your IP address when the app connects, used for security, reliability, and anti-abuse. Server logs are deleted within 30 days.

If the age setting is 13 or older: the account identifier above is also used to sync learning data across devices, and we additionally collect:

• Learning data: watch progress, watch history, favorites, annotations, and resume playback position, associated only with the anonymous identifier above.
• Anonymous crash and error diagnostics: error type, app version, OS version, and a short history of recent in-app actions used to reproduce bugs — collected on our own servers, not linked to any identity, deleted within 30 days.
• Problem reports (submitted by a grown-up in the parents area): the message you type, an optional screenshot you choose to attach, and app version — used solely to diagnose and fix the issue, stored only on our own servers, deleted within 90 days.

If the age setting is under 13: the account identifier is used only for the internal operations described above (account authentication, subscription validation, and content delivery). We do not collect learning data or diagnostics from under-13 users:

• Learning data stays on the device: progress, watch history, favorites, annotations, and resume position are saved only on this device. They are not uploaded, do not sync across devices, do not transfer to a new device, and are excluded from device backups.
• No diagnostics or in-app reports: crash/error diagnostics and in-app problem reports are not sent from under-13 devices; parents can contact us by email at any time.

How identifiers are used — and never used

The identifiers described above are used only for internal operations: account authentication, subscription validation and renewal, refund detection, content delivery, security, and keeping the service reliable. We use technical and organizational measures (separate storage; no linkage to names, emails, or other identifying information; access restrictions) to ensure they are not used to contact a specific individual, for behavioral advertising, or to build a profile of a child. We do not collect names, email addresses, locations, or contacts from any user. No third-party advertising or analytics SDKs are included in the app, and we never sell or rent data.

Sharing

We do not sell, rent, or share your data with any third party for advertising, analytics, or any other purpose. The only external services involved are Apple / Google (to process payments), Alibaba Cloud (to host data and stream video content), and an error-monitoring service (to receive anonymous technical error information, such as error messages and stack traces, so that we can keep the service reliable), each processing data solely to provide that service for us.

Retention

• Account identifier and subscription records: retained while the account exists, and deleted when you delete your account; never retained longer than needed for the purposes above.
• Learning data (13+): retained while the account exists; deleted when you delete your account.
• Learning data (under 13): stays on the device until it is deleted in the app or the app is removed.
• Server logs: no longer than 30 days. Problem reports: no longer than 90 days.

Data storage and transfer

Your data is stored on servers located in Singapore (Alibaba Cloud). By using the app, you agree to the transfer and storage of your data in Singapore, which may be outside your country of residence. Where required by applicable law, we rely on appropriate safeguards for such transfers.

Video content is streamed from Alibaba Cloud with encrypted transmission (HTTPS).

If you sign in with Apple, we store the authorization tokens provided by Apple, used only to revoke your Sign in with Apple session when you delete your account. These tokens do not contain your name or email.

Children's privacy (COPPA)

Mathsight complies with the Children's Online Privacy Protection Act (COPPA), including its amended Rule (published April 22, 2025; effective June 23, 2025). For users identified as under 13, the only personal information we collect is a persistent identifier, used solely to provide support for the internal operations described above — consistent with 16 C.F.R. §312.5(c)(7). Under-13 learning data stays on the device and is not collected by us. Where the GDPR applies, a parent or legal guardian should review this policy and manage the child's account.

Parents and legal guardians may request access to, or deletion of, their child's data at any time by contacting us at mathsight@timebook.xin. We will verify the request as appropriate and respond without undue burden. (For under-13 users, most data lives only on the device and can be deleted directly in the app.)

Your rights

Depending on your jurisdiction, you may have the right to access, correct, or delete your personal data, restrict or object to its processing, request data portability, and withdraw consent. You can exercise many of these rights directly in the app (for example, by deleting your account in the Grown-ups area), or by contacting us at mathsight@timebook.xin.

You can delete your account and all associated data at any time in the app's Grown-ups area (Delete Account). Note: deleting your account does not cancel your subscription — you must cancel it separately in the App Store to stop being charged.

Contact: mathsight@timebook.xin