About Capo

Capo is made by Kurbo under the Sonid brand — the music theory learning ecosystem used by students and teachers worldwide.

Where Sonid teaches harmony step by step — with lessons, exercises, and ear training — Capo is the practice surface for string players. It answers the question: where does this chord or scale live on my neck?

Sonid + Capo

• Sonid — structured theory education, articles, audio, and quizzes
• Capo — interactive fretboard for guitar, bass, ukulele, mandolin, and more

The apps share theory data, localization, and deep links. Read about a chord in Sonid, then open the same symbol in Capo to study it on the fretboard.

Open source building blocks

Capo for iOS is built on shared Swift packages in this monorepo — tonal analysis, fretboard layout, and Directus-backed theory articles — so improvements to the theory engine benefit both products.

Questions or feedback? Reach us through sonid.app.