Which leak sensors work with Apple Home, Alexa, and Google Home?

Aqara sensors paired with a compatible Aqara hub support HomeKit, Alexa, and Google. Govee Wi-Fi detectors integrate with Alexa and Google but not HomeKit. The Shelly Flood Gen4 is one of the few units in this roundup with native Matter support, which lets it bridge into Apple Home, Google Home, SmartThings, and Alexa without vendor-specific cloud lock-in.