ESP8266 Wifi Module | ESP8266 ESP01 | ESP 01ESP8266 esp01 is a low-cost Wi-Fi chip with full TCP/IP stack and hence ?MCU (micro-controller unit) capability produced by the Shanghai-based Chinese manufacturer, Espressif Systems.The chip first came to the attention of western makers in August 2014 with the ESP 01 module(ESP 01). Hence AI-Thinker is a third party manufacturer. ?So this small module allows microcontrollers to connect to a Wi-Fi network?and make simple TCP/IP connections using Hayes-style commands. However, at the time there was almost no English-language documentation on the chip and the commands it accepted. So very low price and the fact that it was very few external components on the module hence so which suggested that it could eventually be very inexpensive.