Centerline Privacy Policy

Microphone

Centerline requests microphone access only to determine the pitch of an instrument. Audio is analyzed in real time on the device. It is not recorded, saved, transmitted, or shared.

On Android and iPhone, microphone capture runs only while Centerline is on screen and in the foreground. The moment Centerline is no longer the app in front of you it stops: switching to another app, opening the recent-apps list, a dialog or a call taking over the screen, and the screen turning off are all cases of that one rule.

Split screen is the case worth stating rather than leaving to inference. On Android 10 and later the system keeps every visible app resumed, so Centerline running beside another app keeps listening while you work in that other window. That is deliberate: a tuner propped next to a tab or a lesson is a real way to use it, and it is still on screen in front of you. On Android 9 and earlier the system pauses whichever window you are not using, so there Centerline stops the moment the other app takes focus.

A Mac works differently. On a Mac, Centerline can keep listening while its window is open and showing, including while you work in another app beside it. It stops when you minimize its window, hide Centerline, close its window, or quit it. macOS shows its microphone indicator in the menu bar whenever an app, Centerline included, is using the microphone.

Centerline runs no background service on any platform, so it never captures audio after it has left the screen. While a reading is in progress Centerline asks the system to keep the screen awake so you can watch the meter with both hands on the instrument; that request is dropped the moment capture stops.

App data collection and sharing

Centerline 1.5.3 introduces optional Usage analytics. The description below applies only to versions that offer this setting. Centerline 1.5.2 does not include Usage analytics.

Starting with the version that offers Usage analytics, this optional setting is off until you choose to enable it. Until then, the app sends no Usage analytics requests or events. If you enable it, Centerline sends a limited, closed set of screen and feature interactions, broad platform information, and approximate location (country, region, and city) derived from the IP address of the analytics request, plus fixed outcome states and a small set of technical failure categories to Endpaper Labs' self-hosted analytics service. This helps us understand which features work well without measuring the notes you play.

Usage analytics uses a random temporary session identifier held only in memory so a short sequence of app events can be counted together. It rotates when the app restarts, when you turn analytics off or on again, and after 30 minutes continuously in the background. It is not a persistent install, advertising, or account identifier, and it is not linked to RevenueCat or store purchase records. The app does not request location permission or send GPS coordinates. Usage analytics uses no cookies and does not track activity across other companies' apps or websites. The apps contain no advertising or Centerline account system.

Centerline never sends microphone audio, recordings, detected pitch, notes, cents, strings, tuning content, support text, receipts, order or transaction identifiers, purchase tokens, prices, currencies, device model, screen size, or arbitrary error text as Usage analytics. Tuning remains available offline; the optional analytics request never controls tuning, audio capture, or a purchase.

To report purchases and refunds, the App Store and Google Play may separately send limited transaction records to RevenueCat, which Endpaper Labs uses as a purchase-reporting service. The Centerline apps do not send those reports themselves. That store-to-service reporting does not include microphone audio or Usage analytics from Centerline, and it is not joined to the temporary analytics session identifier.

Website analytics

The Centerline marketing website, including this policy page, uses a self-hosted Umami installation at analytics.wyatt-fleming.com. The website may record the page or event URL after campaign-only sanitization, referrer and campaign values, selected interactions, browser, operating system, device, screen size, language, Core Web Vitals, and coarse location derived when the request is received.

Website analytics uses no cookies, does not track activity across websites, and honors the browser's Do Not Track setting. Only registered utm_source, utm_medium, utm_campaign, and utm_content values may remain in a recorded URL. Every other query parameter, including paid-keyword and ad-click identifiers, and the URL fragment is removed before analytics is sent. Umami's analytics database has no IP address column. Hosting and security logs may separately process and retain network metadata. Website measurement is separate from the optional in-app Usage analytics described above and has its own controls.

Purchases

Centerline's optional unlock is a one-time purchase. Payment is processed by the store where you buy it: Google Play on Android, or the App Store on iPhone and Mac. Centerline does not receive payment-card details and does not require a Centerline account.

For purchase and refund reporting, the store may send RevenueCat a transaction record. Depending on the store and event, that record can include a product identifier, transaction and original-transaction identifiers, purchase or refund time, price, currency, store, purchase environment, and a store receipt or purchase token. RevenueCat processes those records for Endpaper Labs. Its handling of that service is described in the RevenueCat Privacy Policy.

The app itself stores only whether the unlock is owned, on your device, alongside your tuning preferences. How Apple and Google handle payment information is described in their own privacy policies.

App data retention and deletion

Centerline stores tuning preferences and local unlock state on your device. Uninstalling the app on Android or iPhone removes them. On a Mac, macOS can keep them in the app's container folder (~/Library/Containers/com.endpaperlabs.tuner) after the app is deleted, until that folder is removed. If you enable Usage analytics, its event records older than 26 months are removed by a weekly pruning job. Turning the setting off stops future analytics requests and clears pending in-memory analytics work. To ask about access to or deletion of analytics records, email wyatt@endpaperlabs.com. Because the temporary session identifier is not retained by the app or linked to an account, we may not be able to locate a specific analytics record on request.

Endpaper Labs retains purchase-reporting records only for purchase and refund reporting, preventing duplicate reports, and meeting applicable legal obligations. To request access to or deletion of a purchase-reporting record, email wyatt@endpaperlabs.com. We will verify the request and respond under applicable law; a record may be retained when necessary for legal obligations or to resolve a purchase or refund.

Children

Centerline does not knowingly collect information from children.

Changes

If this policy changes, the effective date above will be updated. A future version that changes the app's data practices will disclose those changes before release.

Contact

Questions about this policy or the app: wyatt@endpaperlabs.com

Endpaper Labs LLC