Thrumline

Last updated for version 1.1.

The short version

Thrumline collects nothing, sends nothing and has no network access. Everything it shows comes from a Bluetooth sensor near you and stays on your Mac, including any sessions you choose to record.

This policy covers Thrumline on Mac, on iPhone and iPad, and on Android. Wherever it says “your Mac”, the same holds for your iPhone, iPad or Android device: nothing is collected, nothing is sent, and everything stays on your device.

What Thrumline reads

Thrumline connects to a Bluetooth heart rate sensor and reads what the Bluetooth standard defines for one: the heart rate measurement, the beat-to-beat intervals where a sensor sends them, whether the sensor believes it is touching skin, where on the body it says it is worn, and its battery level.

It reads nothing else from your Mac. It does not read your files, your contacts, your location, your calendar, your health records or anything else.

Where it goes

Nowhere. Thrumline has no network entitlement, which means macOS itself will not let it open a network connection. There is no server to send anything to, no analytics library, no crash reporter and no account.

This is not a promise about how the data is handled once collected. It is a statement that it is never collected in the first place.

What is stored, and where

Inside the app's own sandbox container on your Mac, Thrumline keeps your preferences: your age or measured maximum heart rate, your weight and which of the two calorie formulas to use, the identifier and name of the sensor you last chose, and your display settings.

The live readings are held in memory only. The chart keeps the window you choose — one minute, five, fifteen or an hour — and the figures since the last reset run from when the app started or was last reset. None of that is written to disk, and it is gone when Thrumline quits.

Recorded sessions (version 1.1 and later) are the exception, and only when you record one: Thrumline then keeps that session's heart rate for each second, with its start and end, in the same container, so you can look back at it. It keeps your 50 most recent sessions and removes older ones. You can delete any session at any time, and none of them leaves your Mac unless you export it yourself as a file.

If you switch on a zone alert delivered as a notification, macOS asks you for permission to show notifications. The notifications are created on your Mac and are not sent anywhere.

Deleting the app removes its container and everything in it.

Bluetooth

macOS asks for your permission before Thrumline may use Bluetooth. The app scans only for the standard Heart Rate Service, connects to one sensor at a time, and does nothing else with the radio. It does not pair with, read from or advertise to anything else.

iPhone and iPad

iOS asks for your permission before Thrumline may use Bluetooth, and Thrumline uses it only to read your heart rate strap. While a strap is connected, Thrumline keeps reading with the phone locked or the app in the background. While you record, a Live Activity shows the reading on the Lock Screen; it is made on your device and sent nowhere.

Apple Health is optional and off until you switch it on. Only then does iOS ask for Health permission, and Thrumline writes each recorded session to Health as a workout with its heart rate. It only writes: it reads nothing from Apple Health. Your settings and recorded sessions stay on your device.

Android

Android asks for the “Nearby devices” permission so Thrumline can find and connect to your strap. Scanning never uses your location, and Thrumline requests no location permission. While a strap is connected, a notification shows the reading (a foreground service keeps Bluetooth running); it is shown on your device and sent nowhere.

Health Connect is optional and off until you switch it on. Only then does Android ask for permission, and Thrumline writes each recorded session to Health Connect as an exercise session with its heart rate. It only writes: it reads nothing from Health Connect. Your settings and recorded sessions stay on your device; Android may include them in your own device backup.

Children

Thrumline collects no personal information from anyone, of any age.

Changes

If this policy ever changes, the new version will appear on this page with a new date. Any change that affected what the app collects would also be described in the release notes, because it would be a change to what the app does.

Contact

Questions about this policy, or about anything else: support@khangazun.com.