Wi-Fi devices must have a public local or a cloud API. Local API integrations receive higher priority, whereas cloud based integrations have a low priority. With that being said, if devices using cloud are highly popular, they may receive engineering resources allocated much faster - some examples of cloud based integrations are Rachio, Ecobee, and other popular brands.
We are very fortunate that this awesome community often steps in and fills the gap where our engineering resources may be scarce. For complete list of compatible devices that have been tested by our engineers, please check out this document: List of Compatible Devices | Hubitat Documentation
For community maintained integrations please check out this thread: Custom Device Drivers [Wiki]
