1. Who we are
Metrum: Metronome & Setlists (the “App”) is developed by Marcin Karwat. Marcin Karwat is the controller responsible for the personal data processing described in this policy.
Postal address: Marcin Karwat, Wojska Polskiego 27, 68-132 Sanice, Poland. Privacy enquiries: metrum.metronome.contact@gmail.com.
Metrum stores your library and practice history on your device. If you connect your Google account and use cloud sync, the App also stores sync copies in your own Google Drive. The Developer does not operate a server that receives your library or practice history.
2. Data the App handles
- Your library: song titles, authors, notes, tempo and rhythm settings, tags, setlists and their ordering, arrangement sections and cue text.
- Practice history: practice start times and durations, song-title snapshots, tempos, rhythm settings, section names and associated tags.
- Settings and sync records: preferences, purchase entitlement status, record identifiers, modification times, deletion markers, pending sync uploads and last-sync information.
- Google profile, when you sign in: your email address, Google account identifier, display name and profile photo. These identify the connected account, display your profile and keep sync records associated with the correct account. The App obtains an OAuth access token to communicate with Google Drive.
- Purchase information: Google Play supplies purchase status, product identifiers and purchase tokens so the App can acknowledge purchases and unlock or restore premium features. The App does not receive your card number or payment credentials.
- Support correspondence: if you contact us, we receive your email address, message and any attachments or diagnostics you choose to send. Please avoid sending unnecessary personal or sensitive information.
The App has no advertising, analytics or remote crash-reporting service. Practice statistics are calculated from your practice history; they are not an advertising or tracking feature.
3. Optional Google sign-in and Drive sync
You can use the App’s local features without connecting a Google account. Cloud sync is a premium feature that requires Google sign-in, the relevant Google permissions, an internet connection and sufficient Google Drive storage. Once connected and enabled, sync can run automatically as well as when you request it.
The App requests the drive.appdata permission to read and write its own hidden application data folder. This permission does not grant general access to your other Drive documents. Sync files are separate from your ordinary Drive files and from Android device backups.
Sync uploads the library, arrangement sections, practice history and synchronization records described above directly from your device to Google Drive, and downloads and merges them on your connected devices. These are data records, not audio recordings or uploaded music files. The Developer does not receive a copy through a separate backend.
Google provides sign-in and cloud storage and handles data under its Privacy Policy. We use Google data only to provide account identification and the App’s visible sync features. We do not sell it, use it for advertising or use it to train general-purpose AI models.
Metrum’s use of information received from Google APIs complies with the Google API Services User Data Policy and the Google Workspace API User Data and Developer Policy, including their Limited Use requirements.
4. Purposes and legal bases
Where the GDPR applies, we process the data needed to provide your requested App features, account identification, sync and premium purchase handling to perform our agreement with you (Article 6(1)(b)). Connecting Google Drive is optional and requires your authorization. You can stop using it at any time as explained below.
We process support correspondence where necessary to respond to requests about that agreement, or on the basis of our legitimate interest in answering enquiries, resolving problems and protecting legal claims (Article 6(1)(f)). We may retain information where required to comply with a legal obligation (Article 6(1)(c)). If a separate activity requires consent, we will request it before that activity and you may withdraw it.
We do not use your data for automated decisions producing legal or similarly significant effects, or for profiling.
5. Service providers and disclosures
Google handles Google sign-in, Drive sync, Google Play purchases and, when enabled on your device, Android backup. Payment processing is described in the Google Payments Privacy Notice. Support email is hosted by Gmail. We may disclose support information where necessary to comply with law or establish, exercise or defend legal claims.
This policy website is hosted on GitHub Pages. GitHub may process technical request information, including IP addresses, when you visit it, as described in the GitHub Privacy Statement. We do not add analytics, advertising cookies or third-party font requests to these pages.
Google and GitHub may process information outside your country, including outside the European Economic Area. Their privacy notices explain the locations and transfer safeguards they apply, including adequacy decisions and standard contractual clauses where applicable. Contact us if you need information about a transfer involving data we control.
6. Storage and security
Your library, history and preferences are stored in the App’s private storage on your device. Drive communication uses HTTPS and authorized Google access tokens. Sync files are JSON data; the App does not add end-to-end encryption or a separate password to them. Google controls the security of its services, and your device and account security also matter.
The App permits Android system backup. Depending on your Android version, device settings and backup provider, local App data may be included in a cloud backup or device transfer independently of the App’s Drive sync setting. Manage those copies through your device’s backup settings and provider.
No storage or transmission system can guarantee complete security. Protect your device and Google account and contact us if you suspect a problem.
7. Retention and what item deletion means
Local library and practice records remain in App storage until that storage is cleared. Deleting a song or clearing practice history marks records as deleted so that the deletion can sync between devices; it does not immediately erase the record’s stored fields.
Drive sync retains historical snapshots and deletion records indefinitely until the App’s hidden Drive data is removed. Earlier snapshots can contain the content of items you have since deleted. The current App does not automatically expire those snapshots or offer permanent erasure of individual records across all stored copies.
Signing out, disabling sync or uninstalling the Android App does not itself delete the hidden Drive sync data. Signing out also does not itself revoke Google permissions. Previously accepted uploads may remain even if a sync operation is stopped.
Support correspondence is kept only as long as needed to resolve your enquiry and related follow-up, or to meet an applicable legal obligation or establish, exercise or defend a legal claim. Google, GitHub and your backup provider apply their own retention rules to records they control.
8. Stop sync or permanently remove your data
Deleting an item in the App is different from erasing stored copies. To remove the entire library and history from local and cloud storage, follow all the relevant steps below. This cannot be undone.
- Stop sync on every connected device. Disable cloud sync in Settings or sign out by tapping your Google profile in the navigation drawer. Do this before deleting cloud data to prevent another device from uploading it again.
- Remove the cloud copies. Open Google Drive on the web, go to Settings → Manage apps, find Metrum, and use its Options menu to delete hidden app data. See Google’s guidance on hidden app data. This removes the App’s cloud library, history and historical sync files, rather than your unrelated Drive documents.
- Revoke access if desired. Remove the App’s access in your Google Account connections. Revocation stops future authorized access; it is not a substitute for deleting stored copies.
- Clear local copies on every device. In Android Settings, open Apps → Metrum → Storage (or Storage & cache) → Clear storage/data. Menu names vary by device. This removes your local library, history and App settings.
- Check device backups. Remove any remaining Android backups using your backup provider’s controls, and avoid restoring a backup containing the old App data. Reconnecting sync from a device or restored backup that still contains your data can upload it again.
The App does not create a separate Developer-hosted account. Your Google account belongs to you and is not deleted by these steps. We cannot remotely erase data from your device or access your Drive to delete it for you. If you need help, or want to request deletion of support correspondence held by us, contact metrum.metronome.contact@gmail.com.
9. Your privacy rights
Subject to the conditions of applicable law, you can request access, correction, erasure, restriction of processing and data portability, and object to processing based on legitimate interests. You can withdraw any consent without affecting the lawfulness of earlier processing. Contact metrum.metronome.contact@gmail.com to exercise these rights or obtain help with data held on your device or by Google.
We may request proportionate information to verify your identity. Where the GDPR applies, we normally respond within one month; if an extension permitted by law is necessary, we will explain why. You can complain to your local data protection authority or Poland’s President of the Personal Data Protection Office (UODO).
10. Children
The App can be used for music learning. Where local law requires a parent or guardian’s authorization for a child’s use, purchase or Google connection, that authorization must be obtained. We do not use children’s data for advertising or profiling. A parent or guardian can contact us for help with privacy or deletion.
11. Changes and contact
We will update the date on this page when the policy changes. For material changes to data handling, we will provide an appropriate notice in the App before the change takes effect and obtain consent where required. A policy update does not by itself authorize a new use of your Google data.
Privacy questions: metrum.metronome.contact@gmail.com. Postal address: Marcin Karwat, Wojska Polskiego 27, 68-132 Sanice, Poland.