FEATURES:

Hardware IO similar to Arduino
Sophisticated hardware IO API that can significantly cut down on duplicate device configuration and manipulation effort.
Lua script code that is interactive, similar to Arduino code.

 
Nodejs style network API
An event-driven API for network applications in the Node.js style makes it easier for developers to write code that runs on a 5mm*5mm MCU.
greatly accelerate the development of your IOT applications.
 
Cheapest WiFi
The ESP8266 is a low-cost, easily prototypable development board with an inbuilt WiFi-MCU module. The most affordable platform for developing IOT applications.
The ESP8266-based development board combines GPIO, PWM, IIC, 1-Wire, and ADC onto a single board. With the help of NodeMCU Firmware, accelerate your development!
 
SPECIFICATIONS:
 
Input Voltage: 7 – 12V
Clock Speed: 80 MHz (5x Arduino UNO or Mega)
SRAM: 64 KB
Flash Memory: 4 MB
Dimensions: 49 x 24.5 x 13mm
Current: 215mA
External QSPI flash: 512 KB to 4 MB* (up to 16 MB is supported)
Digital I/O Pins (DIO): 16
I2Cs: 1
SPIs: 1
UARTs: 1 on dedicated pins, plus a transmit-only UART can be enabled on GPIO2
Analog Input Pins (ADC): 1
WEP or WPA/WPA2 authentication, or open networks
64 KB of instruction RAM, 96 KB of data RAM (80x Arduino UNO!)
512 KB of EEPROM (512x Arduino UNO!)
CPU: 32-bit RISC Tensilica Xtensa LX106 running at 80 MHz
Operating Voltage: 3.3V
 
PACKAGING LIST:
 
1 x NODEMCU V2- ESP8266