Matrix: Privacy Policy

Last updated: 26 September 2026

Matrix is an offline app for learning linear algebra and related maths. It is made by Oli Holder.

What the app stores

Matrix saves your learning progress on your device only, in the app's local storage:

• which lessons you have finished and the last card you reached in each
• which checks and boss rounds you have passed
• your drill history (how many you answered, how many were right, when each drill type is next due)
• your best scores in the games
• whether you have already seen the welcome screen

This data never leaves your device. Uninstalling the app, or clearing its storage in Android settings, deletes it.

What the app sends

Nothing. Matrix does not collect, transmit, sell or share any personal or usage data. There are no accounts, no ads, no analytics, no crash reporting and no third-party tracking SDKs. All maths runs on the device.

Permissions

The Android package declares the standard internet permission that the Capacitor framework includes by default. The app does not use it to send or fetch any data.

Children

The app collects no data from anyone, including children.

Changes

If this policy changes, the new version will be published at the same address with a new date.

Contact

olivermholder@gmail.com