NodeMCU is a versatile board with the WiFi-enabled ESP8266 system-on-chip, USB to UART bridge, voltage regulator and some auxiliary components. With a price tag of about $9 on Aliexpress it allows you develop your own Internet “things” literally in minutes. The killer part is a build-in Lua interpreter, so no toolchain or development kit is required. The language is pretty easy. Text files containing Lua scripts are simply uploaded to the board and executed directly by the interpreter inside ESP8266. You can also type the commands directly via the terminal. NodeMCU firmware can also be uploaded to any ESP8266 module like the ESP-01, ESP-07 or bare ESP-12.