Not sure why you are being down voted, this is essentially how Spotify's shuffle works. At least, if you MITM the official client and load a large playlist/cont

Not sure why you are being down voted, this is essentially how Spotify's shuffle works. At least, if you MITM the official client and load a large playlist/context you'll only see a small window worth of tracks being loaded. And you won't see any request from the client when you then shuffle that playlist, it's done locally. This may, of course, have changed. My experiments while (badly) implementing librespot's shuffle functionality were a few years ago now.