In building that, I found that I could make really interesting mixes of cross-genre music, especially from playlists of friends.
The built-in Spotify mixing forces you into a funnel of connecting Spotify membership collaboration and is terrible for using the playlists of interesting strangers. It also wants to use AI on everything and also modifies the original playlists.
I spent the last couple of months building out a web app for it. I wanted to explore three.js and Svelte more. It was great for that. Although I used Claude fairly often, I backed off because I actually wanted to learn the libraries I was using.
It's free. I hope the Spotify API rate-limiting holds up to general use like this.