What Bolus reads from your CGM

Bolus reads your glucose readings, and only your glucose readings. Here is what that means for each monitor.

What is read

A glucose reading is the value, the time it was taken, and sometimes which way it is trending. Your monitor takes these every few minutes, and Bolus reads them so it can show your timeline.

• FreeStyle Libre: Bolus reads your glucose history from LibreLinkUp, read-only. It cannot change anything in your Libre account.
• Dexcom: Bolus reads Blood Glucose from Apple Health, read-only. It never writes anything back to Health, and it does not see your name or Dexcom login.

What is not read

Bolus does not read anything else from your monitor or from Apple Health. No other health data, no location, no contacts. On the app as a whole, the only two device permissions Bolus asks for are Apple Health for blood glucose and notifications.

Where your credentials sit

For FreeStyle Libre, your LibreLinkUp login stays in your iPhone’s secure keychain and is never stored on Bolus servers. For Dexcom, there is no login to store, because the connection goes through Apple Health.

To understand how the readings are shown and used, see how your glucose is used.