My plan was to start a webradio via the REST-Api.
The API works perfect but i can’t start webradios.
It seems like the playlist names for getting the JSON output of webradios (“radio-favourites” and “my-web-radio”) cant’t be used with the “api/v1/commands/?cmd=playplaylist&name=” request of the API. Or am i doing something wrong and there is another way of starting webradio stations via the api?
Thanks for the help.
Don’t think so … needs someone to extend the API with a PR.
Thanks for the answer.
I found a workaround described in this thread: https://forum.volumio.org/add-webradio-playlist-t7023.html
Toni0 suggests adding the webradio station to the queue and then saving the queue to a playlist wich then could be played via the REST API.
This only beeing a workaround maybe i’m going to post a feature request.
Maybe you can’t start a volumio webradio, but i found out that it’s possible to play a webradio url via the API
using the url volumio.local/api/v1/replaceAndPlay
and then posting the data, in this case for wefunkradio 
{
"service": "webradio",
"type": "webradio",
"title": "WEFUNK",
"uri": "http://s-09.wefunkradio.com:81/wefunk64.mp3"
}