Privacy Policy

Circle of Thirds is an interactive music theory app for iOS. This page explains what data the app handles.

What the app collects

Nothing. The app does not collect, transmit, or share any personal information, and has no user accounts or backend.

Data stored on your device

• Settings and preferences. Your selections (key, scale, chord buttons, layout, theme, MIDI options, and similar) are stored locally on your device using the system's user-defaults storage. They never leave the device and are removed when you delete the app.
• MIDI. If you connect a MIDI device or virtual MIDI source, the app reads incoming notes and can send notes to MIDI outputs you choose. All MIDI processing happens on-device. No MIDI data is recorded or transmitted off the device by the app.

Pro in-app purchase

Pro is unlocked through Apple's StoreKit. The app checks your purchase entitlement with Apple to know whether Pro features should be enabled, and uses Apple's standard Restore Purchases flow when you tap it. The app does not see your Apple ID, payment method, or billing details, and does not send purchase information to any other server. Billing and refunds are handled by Apple under your App Store account.

No analytics, advertising, or tracking

The app contains no third-party analytics, advertising, attribution, or tracking SDKs, and does not use the Advertising Identifier (IDFA). Nothing is sent to any server operated by the developer.

Children

The app is suitable for general audiences and does not knowingly collect personal information from anyone, including children.

Data sharing

There is no user data to share. The app does not sell, rent, or trade personal information.

Changes

If this policy changes in a meaningful way, the updated version will be posted on this page with a new "Last updated" date.

Contact

A contact form will be available on this site. Until then, questions about this policy can be sent through the App Store listing.