Alexa skills to control ESP8266 without opening a router's port/firewal.
In This project you will be able to control ESP8266 with Alexa skills without opening a firewall port or setuping a revers proxy.
Download this project and unzip.
Copy following folders to "C:\Program Files (x86)\Arduino\libraries"
Update and flash your ESP8266 with "ESP8266/ESP8266_WebSocketClient/ESP8266_WebSocketClient.ino"
Create an Alexa skills and add Heroku app URL as an end-point
Test and enjoy.