The ESP8266 chip first came to critical attention in 2014 with the ESP-01 module. The low cost of the ESP-01 with its Wi-Fi and full TCP/IP stack makes the ESP8266 very popular with makers. The following is a photograph of the ESP-12F, also known as the ESP8266 Wi-Fi Witty Cloud Development board:
Other versions of the ESP-8266 include the ESP-01, ESP-02, and so on.
The ESP-12F features an RGB LED and light sensor. These features allow a developer to easily test out code without having to hook up sensors or LEDs. The ESP-12F may be programmed using the standard Arduino IDE through the removable daughter board that comes with the module.