I’m just starting to look into the Eco Plug as well. I picked up four of them on the Home Depot clearance.
This thread has some code that works with HomeBridge:
https://community.smartthings.com/t/eco-plugs-wi-fi-controlled-outlet-by-kab/34557
There is also some concern of the Eco Plugs sending your SSID and password in plaintext to a server the vendor owns.