Work in progress documentation of Trenitalia's api, check the wiki at https://github.com/SimoDax/Trenitalia-API/wiki/API-Trenitalia---lefrecce.it. I also made an Italo equivalent at https://github.com/SimoDax/Italo-API/wiki/API-Italo
This is not a Viaggatreno documentation, there are many already done, such as https://github.com/bluviolin/TrainMonitor/wiki/API-del-sistema-Viaggiatreno, https://github.com/sabas/trenitalia and https://github.com/Razorphyn/Informazioni-Treni-Italiani