Searched and found this topic… Are you wanting to use IoT Things & shadow states to keep track of device state?
You could build a lambda (w/ AWS API Gateway) to update shadow state, then use the JSON Complete API to send events to the lambda…
Alternatively you could run a local HTTP server which published events directly to the AWS IOT MQTT broker (to the special update shadow state topic)… or published to a local mosquitto that published to AWS IOT MQTT… lots of options as I think through this myself.