What is the “plateform:” key used for ?
What is their valid values?
Thanks a lot for help.
I’ve used Home Assistant for a few years and just added ESPHome a few months ago. I depend heavily on the documentation at the ESPHome web site. The techical writers over there are much more articulate than most of us hobbyist and bit-bangers. (No offense intended to the wordsmiths on this forum. 
)
https://docs.platformio.org/en/latest/platforms/index.html#platforms
Good luck with your journey.
Thanks a lot, it help as it is possible !
I answer to help other with similar question.
On m’y understanding the plateform is referencing some form of library where some commands and status are defined. I dont know place for an exhaustive list .
For example the switch device may have, custom/generic/template/gpio as platform, with differents attributes and methods.