Hey HN, I just launched FretLabs - a web application I've built to make guitar scale practice more engaging and productive. It started as a personal project to give a little structure to my freestyle sessions and has since evolved considerably. If you're familiar with Chordify, it's like that but for scales.

Features:

- 10,000+ song catalog (growing daily), or upload your own MP3s

- Automatic key signature and song section boundary detection

- Dynamic 3d fretboard with customizable scale options/controls

- Left-handed mode, support for 4, 6, and 7 string guitars

I'd love to hear your thoughts, feedback, or answer any questions!