I DJ electronic music and run a YouTube channel with 634,000 subscribers. Every time I went to prepare a mix for the channel, I ran into the same problem. Sorting the playlist by musical notes. Until I thought to myself - with all the tools available today, maybe I can harvest them to my advantage. And that's what I did. The software I use, RecordBox, arranges the notes alphabetically; even in its sorting, it's not really sorted like in the Camelot Wheel. HarmonySet processes your playlist with an algorithm I built and solves the problem in a mathematically perfect way. Next.js, TypeScript, Supabase, deployed on Vercel. 100% client-side, files never leave your browser. https://www.harmonyset.com GitHub: https://github.com/roneni/harmonic-flow Would love feedback on the algorithm, UX, or the AI-assisted development approach.