This isn’t an ESP8266 shield, either: you can write code for the ESP module, connect the serial pins, and hit the program button. The basic functions of the Arduino IDE – pinMode, digitalRead ...

He’s wondering if the ESP8266 is 5V tolerant after all. If it is, great. We don’t need level converters, and interfacing the ESP to USB TTL ... to the 5V pin of an Arduino that still work ...