You could have your skill service have a long-polling endpoint / websocket / open TCP, that your non-echo devices can watch for events. When the skill has been processed, you can just fire the event to all those listening / enqueue it to be done on their next poll.
I'd be very interested in this sort of feature. I'd like to have an Alexa Alerts API that would allow my IoT device to voice alarms using Alexa. For example "Excuse me, but there's someone at the front door." or (in response to the front door opening) "Be careful, it's icy outside!". There's a whole universe of functionality that would be opened up if messages could be pushed to the Echo. I'm working on a bath filling sensor and wanted to have Alexa voice, "Careful, your bath is almost full!" Once I have the faucets internet connected I'd be able to say, "Alexa, turn off the bath water."
curl AVS authentication 3 Answers