NodeMCU is an open source IOT platform.It uses the Lua scripting language. It is based on the eLua project, and built on the ESP8266 SDK 1.4. It uses many open source projects, such as lua-cjson, and spiffs. It includes firmware which runs on the ESP8266 WIFI , and hardware which is based on the ESP-12 module.
It's a lua based firmware for wifi-soc esp8266
Build on ESP8266 sdk
Lua core based on eLua project
cjson based on lua-cjson
File system based on spiffs
Easy to access wireless router
Based on Lua 5.1.4 (without debug, os module.)
Event-Drive programming preferred.
Build-in json, file, timer, pwm, i2c, spi, 1-wire, net, mqtt, coap, gpio, wifi, adc, uart and system api.
GPIO pin re-mapped, use the index to access gpio, i2c, pwm.
Both Integer version(less memory usage) and Float version(Default) firmware provided.