Badly documented. That's the most of the part I can say. Belkin asks you for emailing them if you want to get some documentation.
We connected to the WEMO with a WEB based interface. The only thing we can do is turn on and off anything connected to the WEMO plug. For these requirements, we just need a sad toggle button. This was the workflow:
-Connect WEMO and WEMO app to know the hardware and sw (You need to connect both devices to the same network)
-Connect the WEMO to a network I admin to look for it, knowing its MAC and range of IP
-Create a node js client to request status and send instructions to the WEMO. Server
Two things were vital in this prototype were Tom Igoe's code for Arduino and Wemo-client library for node.js.
THOUGHTS ON THIS.
-They communicate via UPnP
-Client should send POST request
-The client should check current status periodically, being that sometimes the data is inconsistent (e.i It is on and it answers it is off or backwards).
-The client and server exchange a whole XML