I Found that logging into your Ecobee account it makes a request to https://api.ecobee.com/ea/devices/ls?format=json to pull for changes and get a list of all devices with identifiers and full metadata..
Then when you make a state change like turn on or off it makes a PATCH https://api.ecobee.com/ea/devices/ls/ID_HERE?format=json with the state {"state":{"on":true}}.
The following shows off how to get access to a list of all switches via polling
https://github.com/SmartThingsCommunity/SmartThingsPublic/blob/master/smartapps/smartthings/ecobee-connect.src/ecobee-connect.groovy
I Found that logging into your Ecobee account it makes a request to
https://api.ecobee.com/ea/devices/ls?format=json
to pull for changes and get a list of all devices with identifiers and full metadata..Then when you make a state change like turn on or off it makes a
PATCH https://api.ecobee.com/ea/devices/ls/ID_HERE?format=json
with the state{"state":{"on":true}}
.