Universal CGM Data Sidecar That Forces Lingo Glucose Into Apple Health, Cronometer, And Fasting Apps
Abbott's Lingo over-the-counter continuous glucose monitor (and to a lesser extent Dexcom Stelo) ships data into a vendor app that does not export to Apple Health for glucose readings. The fasting and metabolic-health Reddit community is loud about this: they bought the sensor specifically to feed their existing fasting app or Cronometer log, and now the data is trapped. Build a sidecar app that reads from the Lingo BLE stream (or screen-scrapes the vendor app) and writes glucose into Apple Health, Cronometer, MyFitnessPal, and a CSV export.
BLE-direct beats screen-scrape if you can do it. Abbott will not give you a public API; lean into the same legal frame the right-to-repair people use - this is your data from your sensor, you bought both. Don't market this to type-1 diabetics, that's a different (regulated) market - market it to the fasting and metabolic-health crowd who already know they want their numbers in Cronometer.
landscape (4 existing solutions)
Stelo solves the Apple Health half-of-the-problem; Lingo (Abbott) does not. xDrip exists for hardcore users but is overkill. The clean opportunity is a Lingo-specific (initially) sidecar with a quiet Stelo expansion: read from the BLE stream, write everywhere the user wants the data, charge $5-10 one-time. The biomarker-tracking crowd is small but high-LTV.