I one-shotted this app with Claude Opus 4.6 (Claude Code in VS Code), from idea to deployed GitHub Pages site in a single prompt.
Live demo: https://mayerwin.github.io/MIDI-Notes-Player/
It's a simple tool: paste a sequence of MIDI note numbers (like 60, 64, 67, 72) or note names (C4 E4 G4 C5) and hit Play. It also supports solfège (do ré mi fa sol), accidentals (Eb5, sol#4), any separator you want, and 50+ General MIDI instruments via SoundFont samples.
Für Elise is pre-loaded so you can try it immediately.
What Claude generated in one shot: - Vite + vanilla JS app (no framework) - Note parser supporting MIDI numbers, scientific pitch notation, and solfège (with French accidentals like solb, sold) - SoundFont-based audio playback with 50+ instruments - Real-time note validation with visual token display - Tempo/duration controls, keyboard shortcuts, animated playback - GitHub Actions CI/CD for automatic deployment - README, LICENSE, the whole thing
The only manual steps were creating the GitHub repo via gh CLI (which Claude also did through the terminal) and authorizing the push.
Stack: Vite, vanilla JS/HTML/CSS, soundfont-player, Web Audio API.
Source: https://github.com/mayerwin/MIDI-Notes-Player
Comments URL: https://news.ycombinator.com/item?id=47436355
Points: 1
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