[fivebanger]

@andrkac Your JSON-rpc call will not work for at least two reasons:

1.:
As mentioned in the issue, calling the radio.de add-on with just the "id" is not supported yet (will add to next version).

2.:
The JSON-rpc "file" data you provide is erroneous:

from your log
{"jsonrpc": "2.0", "id": 1, "method": "Player.Open", "params": {"item": {"file": "plugin://plugin.audio.radiode/?mode=play_stream&data=%7B%22id%22%3A+%22dalmacija%22%2C"}}}
vs.
{"jsonrpc": "2.0", "id": 1, "method": "Player.Open", "params": {"item": {"file": "plugin://plugin.audio.radiode/?mode=play_stream&data=%7B%22id%22%3A+%22dalmacija%22%7D"}}}

Pls. note "%2C" vs. "%7D" at the end, which will result in "," vs. "}".

An example string for JSON-rpc "file" for the current version of the add-on would look like:
plugin://plugin.audio.radiode/?mode=play_stream&data=%7B%22id%22%3A+%22rockantenne%22%2C+%22name%22%3A+%22ROCK+ANTENNE%22%2C+%22icon_url%22%3A+%22https%3A%2F%2Fd3kle7qwymxpcy.cloudfront.net%2Fimages%2Fbroadcasts%2F31%2F87%2F9112%2F1%2Fc300.png%22%2C+%22stream_url%22%3A+%22https%3A%2F%2Fstream.rockantenne.de%2Frockantenne%2Fstream%2Fmp3%3Faw_0_1st.playerid%3Dradio.de%22%7D