As far as I know, it is not possible to develop a Web app (outside spotify.com) providing a custom Web player which plays Spotify songs, am I right? The only option still seems to be the spotify play button, which is very limited though.
I have just seen, however, this example
1) http://static.echonest.com/enspex/web/ChillRadio/
this one
2) http://lab.possan.se/thirtify/
and this one
3) https://developer.spotify.com/web-api/code-examples/ (see "Play something" snippet)
that seems to use a custom player (2) and 3) are not working for me, though). Is there any non-documented feature?
Thanks