I think you need to be more specific, please take a look at my espbutton pusher, which is using mqtt.
I don’t see any harm in discussing esp8266 here, the border between home automation and other technologies are somewhat blurry. For instance we often post things in depth related to bashscripting etc.
My esp post:
https://community.openhab.org/t/cheap-fog-machine-for-halloween-controlled-by-openhab/