Nodemcu ESP8266 Pinout:
For practical purposes ESP8266 NodeMCU V2 and V3 boards present identical pinouts. While working on the NodeMCU based projects we are interested in the following pins.
Power pins (3.3 V). Ground pins (GND). Analog pins (A0). Digital pins (D0 – D8, SD2, SD3, RX, and TX – GPIO XX) Most ESP8266 NodeMCU boards have one input voltage pin (Vin), three power pins (3.3v), four ground pins (GND), one analog pin (A0), and several digital pins (GPIO XX).