The NodeMcu is an open source card with an integrated WIFI ESP-12E module
 
characteristics
802.11 b / g / n wireless standard
STA / AP / STA + AP support
Standard on 9600 baud

Integrated TCP / IP protocol stack to support multiple TCP client connections (5 MAX)
D0 ~ D8, SD1 ~ SD3: used as GPIO, PWM, IIC, etc., port driver capacity 15mA
AD0: 1 ADC channel
Power input: 4.5 V ~ 9 V (10 VMAX), powered by USB
Current: continuous transmission: ≈70mA (200mA MAX), standby: <200uA
Transfer rate: 110-460800bps
Support for UART / GPIO data communication interface