Music Ear Trainer

Privacy Policy

Last updated October 23, 2026

Music Ear Trainer is an ear-training app. You can use it on the web atkeytrainer.matthew.systems or as an iPhone app, and this policy covers both. It is built to need as little of your data as possible. There are no accounts and no sign-in, so you never give us a name, email address, or password. We do not run ads, we do not use analytics SDKs or advertising trackers, we do not track you across other apps or websites, and we never sell your data. The website keeps simple, cookie-free page counts (see below); the iPhone app has none.

What stays on your device

Your progress and settings

Your levels, XP, streak, practice days, review schedule, chosen session length, chosen instrument, and whether you have finished the intro are stored only on your device. On the web they live in your browser’s storage for this site. In the iPhone app they live in the app’s on-device storage, and like other app data they can be included in your own device backups. None of this is uploaded to us or synced to any server.

What leaves your device

Website page counts (Umami, website only)

The website uses self-hosted Umami to count page views by fixed page category. These counts do not include your answers, scores, progress, URL queries, page titles or referring URLs. Umami does not set analytics cookies, and browser Do Not Track is respected. Counts remain in the self-hosted service until deleted. The iPhone app does not include this website tracker.

Crash and diagnostic reports (Sentry)

To find and fix bugs, the app and the website send crash and error reports to Sentry, a third-party diagnostics service. We configure Sentry with sendDefaultPii: false, with performance tracing turned off, and with no session replays or screenshots. A report can include:

  • technical details of the crash or error, such as a stack trace and a short trail of what the app was doing just before it (for example, which screen was open or which button was tapped);
  • in the iPhone app, reports of the app freezing or being shut down by the system;
  • your device model, operating system and version, browser (on the web), and app version, along with basic device details such as language, time zone, and available memory;
  • a small signal when a session starts, used to measure how many sessions end without a crash;
  • in the iPhone app, a random installation identifier created by Sentry’s software. It is not your name, email address, Apple ID, or any device-wide identifier, it is not linked to your identity, and it is not used to track you.

Sentry’s servers receive your IP address because any network connection carries it, but we have set Sentry not to store IP addresses. This data is used only to diagnose and fix problems. It is never used for advertising or to build a profile of you.

Instrument sounds (GitHub Pages)

The app’s instrument sounds come from the free Musyng Kite soundfont, which is hosted on GitHub Pages (gleitz.github.io), a service run by GitHub. In the iPhone app the piano sounds are built into the app; when you choose another instrument (guitar, violin, cello, or strings), the app downloads that instrument’s sound file. On the website every instrument, including piano, is downloaded this way. As with any web request, GitHub can see your IP address, your browser or device type (user agent), and which sound file was requested. The request carries nothing else: no identifiers, no progress, and no personal details. We do not receive any data from these downloads. GitHub’s handling of this data is covered by the GitHub General Privacy Statement.

The website: hosting

The website is hosted by Vercel. Like any web host, Vercel processes standard request information (your IP address, user agent, and the pages requested) to deliver and protect the site. The iPhone app does not use this service.

What we do NOT collect

  • No accounts: no name, email address, or password.
  • No ads and no advertising identifiers.
  • No game answers, scores or progress in website page counts, and no analytics of any kind in the iPhone app.
  • No cross-app or cross-site tracking.
  • No sale or sharing of personal data with data brokers.
  • No location, contacts, photos, or camera access, and no microphone recording: the app only plays sound, it never records it.
  • No push notifications.

Data retention

Your progress stays on your device until you delete it. Crash and diagnostic reports are kept by Sentry only as long as needed to debug issues and are deleted on Sentry’s standard retention schedule. Because there are no accounts, we hold no server-side profile of you.

Deleting your data

  • On the web: clear the site data forkeytrainer.matthew.systems in your browser’s settings. This removes your progress and settings.
  • On iPhone: delete the app. This removes your progress and settings from the device.

Crash reports are not tied to your identity, so we cannot look them up by person. They expire automatically under Sentry’s retention schedule.

Children’s privacy

Music Ear Trainer is a general-audience app and is not directed at children under 13. We do not knowingly collect personal information from children. The app has no accounts, no ads, and no tracking; website page counts contain no game answers or progress. If you believe a child has somehow provided personal data, contact us and we will help.

Changes to this policy

If the app’s data practices change, we will update this page and the “Last updated” date above.

Acknowledgements

Instrument sounds use the Musyng Kite soundfont as prepared by Benjamin Gleitzman in midi-js-soundfonts, licensed under Creative Commons Attribution-ShareAlike 3.0 (CC BY-SA 3.0).

Contact

Questions about this policy or your data? Email matthew.aberham@gmail.com. You can also visit the support page.