In order to use the ESP-01 Wi-Fi relay module, a programmer/programming adapter is required to program the ESP-01 module (see below). Also it is pretty easy to make your own programmer, or you can ...

But these Arduino-compatible platforms are far from the only microcontrollers available. The flash-based PIC family of microcontrollers is another popular choice.

The Nano ESP32 supports both Micropython and Arduino programming languages, providing a clear path for those already familiar with one platform to easily switch back and forth as needed.