ESP8266 is a highly integrated chip, a complete and self-contained solution for the wifi network. At the same time, ESP8266 is a cheap wifi module compare with other module. Beyond that, ESP32 is the latest low-cost and low consumption wifi module, which integrated Bluetooth and wifi technology and has high performance dual core processor.ESP-WROOM-32 is the latest dual, dual core and wireless communication chip of the ESP32 series.