@rmdejonge:
Daily quotas exceeded and Invalid credentials errors apart, I successfully played yt playlists using jsonrpc directly on the kodi/jarvis/osmc host with the following data param [{"jsonrpc": "2.0", "method": "Playlist.Clear", "params": {"playlistid": 1}, "id": 1}, {"jsonrpc": "2.0", "method": "Player.Open", "params": {"item": {"file": "plugin://plugin.video.youtube/play/?playlist_id=SOME_YT_PLAYLIST_ID"}}, "id": 2}, {"jsonrpc": "2.0", "method": "Player.Open", "params": {"item": {"playlistid": 1, "position": 0}}, "id": 3}]