The short version: Musician Toolkit has no accounts, no ads, and no tracking. Your microphone audio and all your practice data stay on your device. The one thing that can leave your device is an anonymous crash report — and only if you switch that on yourself in Settings. It is off by default.
Musician Toolkit is developed and published by Hrdlicka Apps LLC, based in Iowa, USA. The app is available on the Apple App Store and Google Play. You can reach us at support@hrdlickaapps.com.
The Tuner and Pitch Trainer tools use your device's microphone to detect the pitch of what you're playing or singing, so the app can show you a tuning needle or score a practice attempt. This audio is analyzed instantly, in memory, on your device, and is never recorded to a file, saved, or transmitted anywhere. Musician Toolkit has no backend server, so there is nowhere for that audio to go even if we wanted to send it.
The app asks for microphone permission the first time you open the Tuner or Pitch Trainer, with an in-app explanation shown before the system permission prompt. You can deny this permission and still use the Metronome fully — it needs no microphone access at all.
To be explicit: this pitch and frequency analysis is not biometric identification. Musician Toolkit does not create, extract, or store a voiceprint or any other biometric identifier. Audio exists only transiently in memory while a note is being analyzed, and is discarded immediately after — it is never converted into a persistent, re-identifiable representation of your voice.
Musician Toolkit has no backend server of its own, creates no user accounts, and never transmits your practice data, settings, or microphone audio anywhere.
A small amount of data is saved locally on your device so the app can remember things between sessions: your preferences (A4 tuning reference, haptics on/off, default metronome settings), your calibrated vocal range, and your Pitch Trainer practice history and scores. None of this ever leaves your device, and none of it is tied to any account, because there is no account system.
There is exactly one exception, and it is opt-in: crash diagnostics. If — and only if — you turn on Send crash reports in Settings, technical information about a crash is sent to Google's Firebase Crashlytics service so we can find and fix the bug. This is described in full below. It is switched off when you install the app, and nothing is sent unless you switch it on.
We do not use advertising, and we do not use analytics. We cannot see how many people use the app, which tools they use, or how often.
The Metronome can tap out the beat using your device's vibration motor. This is a local hardware call only and involves no data of any kind.
Like most mobile apps, Musician Toolkit's local app data may be included in your device's own built-in backup — to your Google account on Android, or to iCloud on iOS — the same way your phone backs up its other apps and settings. This is a feature of your device and operating system, not something Hrdlicka Apps does. We have no access to your backups and no way to see this data.
Musician Toolkit includes Google's Firebase Crashlytics so that when the app crashes, we can find out why. It is disabled by default. Nothing is collected or transmitted unless you deliberately turn on Send crash reports in the app's Settings screen, under Diagnostics.
While it is switched on, and only when a crash occurs, the following is sent to Firebase:
We do not attach your name, email address, or any user identifier to these reports — the app never calls Crashlytics' user-identifier feature, because there is no account system to identify you by.
Crashlytics is not analytics. Google Analytics for Firebase is deliberately not included in Musician Toolkit. Crash reports tell us that the app broke and where; they do not tell us what you did in the app, which tools you used, or how long you used them.
Who processes it. Google acts as our data processor for these reports. Data may be processed on servers in the United States and other countries where Google operates. Google's handling is governed by the Firebase Privacy and Security documentation. Crashlytics retains crash traces and their associated identifiers for 90 days.
Turning it off. Open Settings in the app and switch Send crash reports off. Collection stops immediately and nothing further is sent. You can change this as often as you like, and the setting is remembered.
App store disclosures. This collection is declared as "Crash Data" under Diagnostics in our Apple App Privacy label, and as "Crash logs" — marked optional, because you choose — in our Google Play Data safety form.
Musician Toolkit is free. There is an optional tip jar in Settings for anyone who would like to support the app's development. Tipping is entirely voluntary and unlocks nothing — there are no paid features, no premium tier, and no content behind a payment. The app behaves identically whether you tip or not.
Tips are processed entirely by Apple or Google through their own in-app purchase systems. We never see, receive, or store your payment details. Your card number, billing address, and personal details go to Apple or Google, not to us, and we have no way to access them. What we receive is an anonymous payout total from the store — we cannot tell who tipped.
The app stores a single true/false flag on your device recording that a tip has been given at some point, purely so it can say thank you and stop asking. That flag never leaves your device and is not linked to anything.
Refund requests for a tip are handled by Apple or Google under their own policies, not by us.
Musician Toolkit's pitch detection is classical digital signal processing (the YIN algorithm), not a trained machine-learning model. No audio, from you or anyone else, is used to train any AI system, and none ever will be — there is no server for training data to be sent to in the first place.
The CCPA/CPRA applies to businesses that meet certain revenue or data-volume thresholds. Hrdlicka Apps LLC does not meet any of them. Separately, we do not sell or share personal information as those terms are defined under the CCPA/CPRA, and we never have. The only personal information the app can transmit is opt-in crash diagnostics, which are used solely to fix bugs and are never sold, shared for cross-context behavioural advertising, or used for profiling.
If you send a Global Privacy Control signal there is nothing for it to act on, since we already sell and share nothing — but we honor the spirit of it regardless. To stop crash diagnostics entirely, switch Send crash reports off in the app's Settings.
If you use the app without turning on crash reporting, we process no personal data about you at all.
If you do turn crash reporting on, the limited technical data described above is processed on the legal basis of your consent under Article 6(1)(a) GDPR. That consent is exactly the toggle in Settings — we do not rely on legitimate interests, and we do not enable collection and ask forgiveness afterwards.
Google acts as our processor for crash diagnostics, and data may be transferred to and processed in the United States. Google relies on the EU Standard Contractual Clauses and the EU-U.S. Data Privacy Framework for those transfers. Given the very small volume and narrow scope of this processing, we have not appointed a Data Protection Officer, which is not required under Article 37 for processing of this kind.
Musician Toolkit is a general-audience music practice tool suitable for all ages. It contains no advertising, no social features, no user-generated content, and no account system, and it does not knowingly collect personal information from children under 13.
Crash reporting is off by default and must be deliberately switched on in Settings, so no diagnostic data is collected from any user — child or adult — who has not enabled it. If a child has enabled it and you would like those reports deleted, email support@hrdlickaapps.com and we will remove them.
Your practice data is stored on your device and you are in complete control of it. Pitch Trainer practice history and your saved vocal range calibration can both be cleared at any time from the app's Settings screen. To remove everything else, simply delete the app from your device.
If you enabled crash reporting, crash traces held by Firebase are automatically deleted after 90 days. You can stop any further collection immediately by switching Send crash reports off, and you can ask us to delete existing reports sooner by emailing support@hrdlickaapps.com.
If we update this Privacy Policy, we will update the "Last updated" date at the top of this page. Material changes will be communicated through an app update notice. Continued use of Musician Toolkit after any changes constitutes acceptance of the updated policy.
Questions about this policy? Email us at support@hrdlickaapps.com. A real person will read and respond.