Send Email on ESP8266 with Arduino

Sending an email is probably the most convenient way of communicating data or informing us of an event from our ESP8266. It’s cross-platform, works on every device and very reliable. It can alert us when one of the sensors detected something (PIR sensor for movement, MQ2 for air quality or any other environmental sensor).
There are a few ways to get that done, and in this post, I’ll show you my preferable way.