StringTheory is an interactive guitar and bass fretboard tool that puts music theory in your hands — literally. See every scale, chord, and voicing mapped across 24 frets. Explore 33 scales and modes. Master the CAGED system with chord shapes that light up across the neck. Hear reference pitches with a piano-quality tuner. Practice with interactive tools, metronome, and interval training — all in one app, no fluff.

Whether you're learning your first open chords or navigating jazz changes, StringTheory shows you exactly where to put your fingers and why.

Free to start. Pro to master.