Apologies, maybe.

I understood it that I can't use the actual soundcloud app with all its functionality that I'm used to. The same app I use when I'm playing music on my phone. I have to use your client app as that's the one which includes support for nymphcast. That's your client app where you've re-implemented some subset of the functionality I want. Soundcloud could integrate the nymphcast client sdk into their app and then I'd have the same experience I get now with chromecast, but why would they do that?

The plan is to get NymphCast into a 'good enough' state, before sending an inquiry off to various services to see whether they're interested in getting their service on NymphCast.

As they say, you already got the 'no', so why not try to get the 'yes' or 'maybe'? :)

I admire your positivity and it's inspired me to take another look at where I left my (audio only) attempts. I sincerely hope you prove me wrong with getting streaming providers onboard.

For what my failed experience is worth, try getting some internal contacts at these companies. The public, and even "developer", contact channels for Spotify, Soundcloud, Tidal and TuneIn are a dead-end. At least, that has been my frustrating experience. Presumably if you throw them money they take you more seriously.

Yeah, there does have to be something in for them, even if it's just positive PR which they can cash in for more subscriptions or such.