MonkeyC is terrible; kind of like ancient Java without the ecosystem. Building for hundreds of different devices with different screen sizes, buttons and capabilities is tough. But it's the only way to build native Garmin apps. Making it work on the Fenix 5 (2017) was emotional. I was trying to get the WiFi sync to work but it appears that Garmin removed the WiFi capability at some point in the last year (missing symbols) and memory constraits (OOM issues) are real.
I then released it using Garmin's Connect IQ native Trial/Unlock capability - which unbeknown to me has been broken for 2 years - so I had to roll out a custom trial, unlock and payment platform within 14 days before my first potential users tried to buy. I've had 2 successful customers on ~200 downloads already with no marketing - just the app store listing.
But why? The watch is full of rich sensor data (HR, steps, age, VO2 max, GPS, elevation, magnetometer etc.). Sharing it as context with a simple prompt like "Am I fit" or "When is the next bus to X" works surprisingly well.
Works over WiFi (phone optional) or Bluetooth. Compatible with Fenix 5+ (8 years of devices).
Privacy: All API calls are done from the watch - no server-side component.
$4.99 one-time. Happy to discuss MonkeyC/Garmin pain or the BYOK model.