Privacy Policy for Nerd Artisan Piano Tuner

Last updated: August 5, 2026

This Privacy Policy explains how Nerd Artisan Piano Tuner ("the App") handles information when you use it.

Developer: Nerd Artisan
Contact email: [email protected]

Overview

Nerd Artisan Piano Tuner is a piano tuning utility for Android. The App records and analyzes piano sound, stores user-created tuning projects, supports project import/export, provides a Free mode and a Pro mode, and may use Google Play Billing, Google Mobile Ads, and Firebase services.

The App is designed so that piano audio and project analysis are processed on the device. Audio recordings and project files are not uploaded to our backend unless you choose to export or share them yourself through Android's sharing or file-saving features.

Information the App processes

Microphone audio

The App requests the Android microphone permission (RECORD_AUDIO) when you use features that require audio input, such as the Characterizer or Tuner.

Microphone audio is used to analyze piano notes and tuning. The Tuner processes audio in real time. The Characterizer may save note recordings as WAV files inside your local project so that the project can be reviewed, recalculated, exported, or reused later.

We do not transmit microphone audio to our backend. Audio is processed locally on your device unless you export or share project files yourself.

Project files

The App stores piano tuning projects. Depending on the tools you use, project files may include:

note recordings, usually WAV files;
characterization data, such as char.json and pitchraisechar.json;
calculation files, such as calc_*.json;
tuning, pitch-raise, render, and analysis data;
imported or exported project ZIP files.

The App keeps an internal working copy in app-private storage. You may also choose a visible project archive folder through Android's folder picker. When you do this, the App stores and synchronizes project files in the folder you selected. You can also export or share a project ZIP through Android's file-saving and sharing flows.

Files saved to a folder you selected, to Downloads, or shared with another app are controlled by you and by the destination app or storage provider.

Free mode and licensing state

The App uses a small Firebase Cloud Firestore backend to support Free mode and reduce abuse caused by uninstalling and reinstalling the App to reset the free timer.

For this purpose, the App reads Android's ANDROID_ID, combines it with the App package name, and computes a SHA-256 hash locally on the device. The clear Android ID is not stored in Firestore. The hash is used as a pseudonymous device-bound identifier for the Free mode record.

The Firestore Free mode record may include:

the hashed device identifier;
remaining Free mode time;
lockout expiration time, if Free mode is temporarily locked;
daily and consecutive rewarded-ad counters;
the current reward-counter day;
creation and last-seen timestamps;
app version code;
schema version;
Firestore update timestamp.

This data is used only to operate licensing, Free mode limits, reward limits, and reinstall-resistant free-timer behavior. It is not used for advertising profiling or sold to third parties.

Google Play purchases

The App may offer a monthly Pro subscription and a lifetime Pro unlock through Google Play Billing. Purchases are processed by Google Play.

The App queries Google Play for available products and active purchases, receives purchase status for configured products, and uses that status to enable Pro features. Payment details, such as your card number or billing address, are handled by Google and are not received by the App.

Ads and rewarded ads

The App may use Google Mobile Ads / AdMob to show banner ads and rewarded ads. Rewarded ads may be used to extend Free mode time after a completed ad reward.

Google Mobile Ads may collect or process information such as device or app identifiers, Advertising ID where available, IP address, approximate location inferred from network information, ad interactions, diagnostics, and fraud-prevention signals, according to Google's policies and your device settings.

The App does not combine the Free mode device hash with Advertising ID for advertising profiling.

App settings and local preferences

The App stores local preferences such as the current project name, selected archive folder URI, local Free/Pro state, Free mode timer state, reward counters, lockout state, and locally restored purchase status.

These preferences are stored on your device. They may be removed if you clear app data or uninstall the App. Because Android backup is enabled for the App, some app-private data may also be backed up by Android/Google according to your device backup settings.

Diagnostics, analytics, and crash reporting

The App does not currently integrate Firebase Analytics or Firebase Crashlytics as separate analytics or crash-reporting SDKs.

Google Play Billing, Google Mobile Ads, Firebase, Google Play services, Android, or your device manufacturer may still process technical data, diagnostics, service logs, or crash information as part of their own services and platform operation.

Permissions

The App uses these Android permissions:

RECORD_AUDIO: used only for piano audio capture in tuning and characterization features.
INTERNET: used for Firebase Free mode synchronization, Google Play Billing, and Google Mobile Ads.

The App uses Android's file and folder pickers for project import, export, and archive folders. Access to user-selected files or folders is based on the choices you make in Android's system UI.

How we use information

We use information processed by the App to:

provide piano tuning, characterization, calculation, rendering, import, and export features;
save and restore your local project data;
operate Free mode, reward limits, temporary lockouts, and Pro access;
prevent simple abuse of Free mode through uninstall/reinstall resets;
process purchases and restore purchased Pro access through Google Play;
show ads and grant rewarded-ad Free mode extensions where applicable;
maintain app reliability, security, and abuse prevention.

We do not sell your personal data.

Sharing with third parties

We do not share your piano audio or project files with our backend or with third parties unless you choose to export, save, or share those files yourself.

We use the following third-party services or SDKs:

Firebase Cloud Firestore, for Free mode licensing state;
Google Play Billing, for purchases and purchase restoration;
Google Mobile Ads / AdMob, for banner and rewarded ads;
Google Play services and Android platform services required by those features.

These providers may process data according to their own terms and privacy policies:

If you export or share a project ZIP, the receiving app, cloud storage provider, email service, messaging app, or other destination you choose may process that file under its own privacy policy.

Data retention

Local project files remain on your device and in any visible archive folder you selected until you delete them, clear app data, uninstall the App, or delete the files from the selected folder yourself.

Exported ZIP files saved to Downloads or shared with another app remain wherever you saved or shared them until you delete them from that location.

Firestore Free mode records are retained while they are needed to operate Free mode limits, reward limits, lockouts, licensing integrity, and abuse prevention. Because these records are pseudonymous and do not contain your name or email address, we may need additional information from you to locate a specific record if you request deletion.

Google Play purchase records are retained by Google according to Google Play's policies and legal obligations.

Your choices and deletion

You can:

deny microphone permission, though audio-based features will not work without it;
stop recording by leaving the recording feature or closing the App;
delete local projects from the App where supported;
delete files from the visible archive folder or Downloads using Android file management tools;
clear app data or uninstall the App to remove app-private local data from your device;
manage ad personalization in your Android or Google account settings;
manage subscriptions and purchases through Google Play;
contact us to request access, correction, or deletion of data associated with the Free mode backend where technically possible.

Deleting a Free mode backend record may affect Free mode behavior and may require the App to recreate licensing state.

Children

The App is intended for piano technicians, musicians, and other users who need piano tuning tools. It is not directed to children. If you believe a child has provided personal data through the App, contact us so we can review and take appropriate action.

Security

We use reasonable technical measures to protect information processed by the App. Firestore communication uses Google's Firebase infrastructure, and the App stores the Free mode identifier as a SHA-256 hash rather than storing the clear Android ID in Firestore.

No method of storage or transmission is perfectly secure. You are responsible for deciding where to save exported project files and with whom to share them.

International processing

The App may use Google services that process data on servers located in different countries. Where applicable, Google and Firebase process data according to their own data processing terms and privacy commitments.

Changes to this Privacy Policy

We may update this Privacy Policy when the App changes, when SDKs or backend services change, or when legal or platform requirements change. The "Last updated" date at the top of this document indicates the latest revision.

Contact

For privacy questions or requests, contact:

[email protected]