Soon after ESP8266 was launched NODEMCU came in picture. NodeMCU firmware’s first file was committed on 13 October 2014 on GitHub. NodeMCU is like a development kit for ESP8266. It is based on ESP8266 – 12. It has on board USB to serial converter. It can be powered by USB cable.
From the above image one can easily make out the ESP8266 board which is mounted on base board of NodeMCU. So NodeMCU is simply with two more major IC. These are CP2102 and LM1117, which are USB to serial converter and voltage regulator for 5v to 3.3V. It has PCB antenna along with two switches and LEDs.
Features of NodeMCU are exact to that of ESP8266. It provides advanced API for hardware IO, which cuts-off the need to study hardware – So you do not need to study anything about the controller or its registers etc.