I'm a noob. I have an ESP8266 board that I program with Arduino by means of a USB to ESP-01S adapter. I had to solder a button to the adapter between GPIO-0 and GND, and so I can load a program as firmware. My program controls a relay. It works well in the home wifi network.
MY question: what IOT server you recommend me to do this control over the internet. An IOT server free and compatible with Arduino programming.