Does the Shelly Flood Gen4 work with HomeKit, Alexa, and Google Home?
The Shelly Flood Gen4 is a battery-powered water leak sensor with a 2 m leak sensor cable that extends to 150 m.
It has Matter over Wi-Fi by default and Zigbee as an alternate firmware. It suits Home Assistant users, with native support through Zigbee. Google Home, Alexa and SmartThings users reach it through an integration (the maker's cloud).
How the device gets into the platform on this route. The headline is the best route: local before cloud, direct before bridged, core before community. The methodology page lists every level.