Sip
Hydration tracking that never leaves your phone
Kotlin Jetpack Compose · Glance 
Material 3 Log drinks, set goals, watch trends, get reminded — with no account and no server. Everything Sip knows stays on the device.
It’s a small, native Android app: Kotlin, Jetpack Compose with Material 3, DataStore for persistence, and Glance home-screen widgets. It ships on Google Play.