digitalRead notifier

Greetings,

I would like to create a simple circuit with arduino or esp8266 that will digitalRead one of the pins, and if that pin is high i would like to get notification on my phone through wifi that would be the best option, I'm pretty sure I know how to make android app for my phone, but how to do it on arduino / esp8266 ?

One simple method would be to run a web server on your ESP8266 which serves up a web page which shows the status of the pin. On your receiving device, you simply repeatedly call the web page (manually for testing, then through an application for live running), check the status of the pin, and react accordingly.