Privacy Policy
Android sign-in remains optional and is not required for Google Play purchase or restoration. Account handling below applies only in versions with sign-in enabled. This page covers the prepared Android subscription service and does not announce public availability on Google Play.
On-device information
Imported MIDI, practice history, favorites, language, playing preferences and recordings are stored on your device. Recording captures key events and timing for MIDI export, without using the microphone. Personal MIDI and performance data are not automatically uploaded to our servers.
Apple and Google sign-in
If you choose to sign in, Apple or Google authenticates you. Our independent Duo Piano Supabase project processes the provider user identifier, email (including Apple relay email), available name and sign-in state to maintain your account, verify access and handle deletion. On iOS, session credentials are stored in the system Keychain. Android account handling is prepared to store session credentials encrypted with a device-specific Android Keystore key in private app storage, outside the webpage. Android app data and credentials are excluded from this app’s backup and device-transfer configuration. The Android sign-in flow opens your system browser for Google authentication. Signing in does not automatically grant a subscription. Apple private keys are server-side only. The account database is separate from CIP Music and DLing Music Box. Personal MIDI, recordings and practice history are not currently synchronized to the cloud.
Online library and providers
The library downloads catalog information and MIDI from Supabase without uploading your personal files. The backend is hosted in the western United States. Requests may generate IP address, time, request and authentication security logs for service delivery, troubleshooting and abuse prevention. Apple, Google, Supabase and our public support website host process necessary network and service data under their policies. Online services may process information outside your country or region.
Personal MIDI covers (new iOS versions)
iOS versions with this feature enabled allocate covers locally from a prepared image pool. MIDI fingerprints and cover assignments stay on the device. No online AI image generator is called; MIDI, filenames, song titles, notes and file fingerprints are not uploaded. To replenish the pool, the app sends a protocol version, random installation identifier, used-cover count and capacity to the independent Duo Piano Supabase backend. The server converts the identifier to a keyed hash before storing counts and update times, without linking it to an account or email. Records support deduplication, internal replenishment reminders and abuse prevention and are retained as needed to provide replenishment. Rate limiting uses a daily changing hashed network identifier; rate records older than one day are cleared on later requests. Providers may still retain the network security logs described above. The app downloads later image packs over HTTPS and validates them before local storage. Deleting or replacing an import does not recycle its cover. Uninstalling or clearing app data resets local assignments.
Subscriptions and payments
Where available, Apple App Store processes subscriptions. The app uses Apple's product, transaction and subscription status to determine entitlements. We do not receive card numbers or payment passwords. Account deletion, sign-out and uninstalling do not cancel an Apple subscription; cancel separately in App Store subscription settings. Prices, trial eligibility and renewal terms appear in the purchase confirmation. In Android versions with billing enabled, Google Play processes payments. Our independent Duo Piano backend receives the purchase token, product and subscription status, expiry and acknowledgement information to verify and restore membership and process renewal, cancellation or refund updates from Google. Purchase tokens are stored encrypted, with hashed lookup identifiers. A separate Duo account is not required; we do not receive your Google account password or payment card details. A short-lived hashed network identifier is used to limit verification requests. Android and iOS memberships are independent. Manage Android cancellation in Google Play; deletion, sign-out or uninstalling does not cancel it. See the Android Terms of Use.
Use and sharing
We process information to provide accounts, the library, subscription entitlements and support. We do not sell personal data. The app contains no advertising, advertising tracking or third-party analytics SDK. Necessary information is processed by service providers or disclosed when legally required.
Deletion and retention
In versions supporting accounts, use My Page—Account—Delete Account and confirm your request. Apple users must authenticate again to revoke authorization; failed verification does not bypass revocation. Successful deletion removes your online Duo Piano account. Sign-out and account deletion do not automatically clear local files; use local clear and recording delete controls separately. Uninstalling removes app-local data; exported copies, system backups and Keychain information may require separate management. Subscription records are retained as needed for entitlement restoration, payment support, fraud prevention and legal obligations. Contact support for a data request; cancellation and deletion do not remove records that must be retained by law. Account data is retained until deletion; provider security logs, backups and legally required records follow applicable retention rules. You can also request account deletion on our support page without reinstalling the app. Contact us below to request access or correction. Apple-linked accounts require Apple reauthentication for automatic deletion; you may also submit a support request. Uninstalling the Android app removes its app-private stored account state; manage exported copies separately.
Android, families and review access
The Android app is intended for all ages, including children. The current Android version does not create Duo accounts or request a date of birth, microphone, location, contacts or camera access, advertising identifiers or hardware identifiers. A parent or guardian should manage Google Play purchases. Personal MIDI and performance files stay on the device. Essential online delivery, subscription verification and security requests process the network and subscription information described above. Service-provider logs may include an IP-derived approximate region, request time, user agent and service errors. We do not use this information for advertising, profiling or personalized recommendations.
Parents and other users can request access, correction or deletion of Android service data. Do not send a child's full name, birth date, school or personal files. Authorized reviewers may enter a separate review credential in a protected native screen. It is encrypted on the device until cleared or the app is uninstalled, and the server verifies a renewable five-minute access period. Review access does not create an account, paid membership or purchase.
Google Play age verification and parent approval
Prepared Android versions use the official Play Age Signals SDK to check whether Google Play requires verification or parent approval. The app uses only the access and approval status in native memory. It does not read age bands, date of birth, age-assessment source, installation identifiers or approval dates, and does not save these signals, send them to our server or webpage, or use them for analytics or advertising. Google manages its own verification and sharing choices under its Privacy Policy. Optional non-sharing is not treated as proof that a user is a child or unverified. Explicit verification or parent-approval requirements pause app access. Failed checks do not clear an existing requirement; connection, an updated Play Store and Google Play services, and installation through Google Play may be needed. Retry after resolving the requirement in Google Play or Family Link. This does not start or cancel a subscription; manage cancellation separately in Google Play.
Files, support and children
File services and recipients apply their own policies when you import through the system picker, export through system sharing on iOS, or save an export using Android’s system file picker. Support email gives us your address, message and attachments only to address your request; do not send passwords or payment credentials. We do not target children for personal data collection. Contact us if a child supplied account information without appropriate permission.
Contact and changes
Duo Piano is provided by Beijing Dingling Cultural Communication Co., Ltd. Privacy and support: cipmusicstudios@gmail.com. We update this page and date when features or information practices change.