ESP32 is a series of low-cost, low-power system-on-a-chip micro-controllers designed by Espressif in Shanghai, China. It has integrated Wi-Fi and dual-mode Bluetooth radios. It has many of the capabilities of the Arduino and can be programmed with the Arduino IDE software and so is an easy upgrade path to wireless communications for Arduino users.
The ESP32 supports many peripherals such as: capacitive touch, ADC, DAC, I2C, SPI, UART, I2S, PWM. It is appropriate for Internet of Things Projects and enables Bluetooth communications for Smartphone applications.
See Wikipedia: HERE And for LOTS of information, ESP32.net HERE The Espressif Discussion forum is HERE AND See: Neil Kolban's excellent book and ESP32 Guide