Adafruit IO Arduino Library 
Arduino library to access the Adafruit IO REST API on platforms like the FONA, CC3000, and ESP8266. This is a good library for simple send and receive access to Adafruit IO feeds. Unlike MQTT the REST API does not require a connection to be kept alive so it's good for things to periodically need to connect and send/receive values. For example a sensor device that sends sensor measurements to AIO and then enters deep power-saving sleep for a period is perfect to use with this library.
An alternative is the Adafruit MQTT library which uses the MQTT protocol to talk to Adafruit IO. This is good for devices that are always on and need to keep a connection alive to to be quickly notified of changes.
Currently this library supports the send API to send a value to a feed and the receive/last API to get the latest value from a feed.
The supported platforms are the Adafruit CC3000, FONA, and ESP8266 Arduino.