Blynk appears to be a fairly put-together library for not only hooking up any Arduino or esp8266 to a phone through WiFi, but also through the net if desired. Install the app onto your iPhone or ...

Blynk is a platform that has iOS and Android apps that can be designed in minutes to control Arduino, Raspberry Pi, and similar microboards over the internet. Blynk is sort of a prototyping board ...

You usually think of using Blynk with an Arduino, but you can also program the embedded part directly on an ESP8266. I quickly threw together a little prototype joystick.