ESP-01S ESP8266 Wifi Module

Product Description

ESP-01S ESP8266 Wifi Module

1MB (8Mbit) Flash.

AP, STA, AP+STA modes available.
easy to use AT commands.
Internal LWIP interface.
Operating Voltage: 3.3V

Links:
ESP8266-AT Instruction Set
ESP8266-SDK Getting started guide
http://www.instructables.com/id/Getting-Started-With-the-ESP8266-ESP-01/
https://learn.adafruit.com/adafruit-huzzah-esp8266-breakout/overview