NodeMCU is an open source [Lua](https://www.lua.org/) based firmware for the [ESP32](http://espressif.com/en/products/hardware/esp32/overview) and [ESP8266 WiFi SOC from Espressif](http://espressif.com/en/products/esp8266/) and uses an on-module flash-based [SPIFFS](https://github.com/pellepl/spiffs) file system. NodeMCU is implemented in C and is layered on the [Espressif ESP-IDF](https://github.com/espressif/ESP-IDF).
The firmware was initially developed as is a companion project to the popular ESP8266-based [NodeMCU development modules](https://github.com/nodemcu/nodemcu-devkit-v1.0), but the project is now community-supported, and the firmware can now be run on _any_ ESP module.
At the moment the only up-to-date documentation maintained by the current NodeMCU team is in English. It is part of the source code repository (`/docs` subfolder) and kept in sync with the code.