Privacy Policy
Last updated: March 2026
This policy covers what data is collected when you use the ChordFrog website (chordfrog.app) and the ChordFrog iOS app. We collect as little as possible and never sell your data.
Website analytics
This site uses Glyphex for anonymous page view analytics. Glyphex does not use cookies and does not collect personal data.
To count unique visitors without storing personal information, Glyphex creates a temporary ID from a combination of your IP address and browser user-agent string, hashed with a salt that changes every day. The raw IP address is never stored. The ID cannot be used to identify you across days or across sites.
What this means in practice: we can see how many people visited a page and roughly where in the world they are (country level), but we cannot identify or track individual visitors.
No consent banner is required because no personal data is processed and no cookies are set. Glyphex operates on EU infrastructure and its approach is designed to be compliant with GDPR, CCPA, and PECR.
If you want to opt out of even this anonymous analytics, you can do so at glyphex.io/docs/privacy.
No other tracking
There are no advertising trackers, no social media pixels, no third-party scripts beyond Glyphex. No cookies are set by this site.
iOS app
ChordFrog is an ear training app. You connect a Bluetooth MIDI keyboard, play chords, and get real-time feedback. There are also audio quiz modes that need no keyboard. The app has no accounts and no registration — there is nothing to sign up for and no profile to fill in.
What the app collects
Practice progress
Which chords you have practised, mastery counts, and quiz scores.
Stored: on your device and synced to your own iCloud account so your progress survives reinstalls and carries across your devices. The data never touches our servers — it goes directly to Apple's iCloud infrastructure.
Purchase status
A single flag recording whether you bought "Remove Ads".
Stored: on-device only, never transmitted. Re-validated against Apple StoreKit on every launch.
Crash and performance reports
Crash stack traces, iOS version, device model, and app version. 20% of sessions include a performance trace to help catch slow code.
Stored: sent to Sentry on EU servers (ingest.de.sentry.io). No personally identifiable information is included.
Ads (only if you have not purchased "Remove Ads")
Google AdMob serves ads and may collect advertising identifiers (IDFA), device information, and coarse location for ad personalisation.
Your control: you can limit ad tracking in iOS Settings › Privacy & Security › Tracking. The app uses SKAdNetwork for privacy-preserving install attribution. See Google's privacy policy for full details.
What the app does not collect
- No names, email addresses, or any contact details
- No microphone or camera access
- No photos or files
- No precise location
- MIDI data (which keys you press) is processed on-device in real time and never stored or transmitted
- App Store review prompts use Apple's built-in system — no data leaves your device
Your data, your control
To delete your local data, delete the app. This removes everything stored in UserDefaults on that device.
To delete your iCloud practice data, go to iOS Settings › Apple Account › iCloud › Manage Account Storage, find ChordFrog, and delete its data. You can also delete it from any device where you are signed in to the same Apple account.
Contact
Questions or requests: [email protected]