[anhphong]

I built this because I kept exceeding my mobile data cap when tethering.

The problem: macOS doesn't distinguish between home WiFi and iPhone hotspot. I'd finish a Zoom call thinking I was on home internet, only to discover I'd burned through 3GB of cellular data.

Existing options didn't fit:

- TripMode ($15/year) does app blocking - overkill for just monitoring

- Bandwidth+ is free but treats all WiFi the same

Technical approach:

- NWPathMonitor.isExpensive detects tethering vs regular WiFi

- CoreWLAN reads SSID for multi-hotspot profile support (requires Location permission on Sonoma+)

- Pure system frameworks, no external dependencies

Supports multiple profiles so you can track personal phone (15GB cap), work phone (unlimited), travel MiFi separately.

$4.99 one-time. macOS 14+.

Happy to answer questions about the implementation.