Case study · 04 · My own products
Lark
The guitar tutor that listens
An AI guitar tutor that hears you play through your microphone, scores every note in real time, and tells you exactly what to fix.
Designed, built and written byVinay Batra- Role
- Founder. Product, design, and full-stack engineering.
- Timeline
- Apr 2026 - Present
- Built with
- Next.js, TypeScript, Web Audio API, Pitchy, Supabase, Claude API
- Live
- lark.coach ↗
Live siteWatch the 30-second film
Why I built it
Guitar apps don't actually listen
Most guitar apps play you a lesson and trust that you got it right. I wanted one that hears what you actually play and tells you what went wrong.
What it does
Note-by-note scoring, then a coach
Lark listens through your microphone and detects every note and chord in the browser as you play. Each note turns green when you hit it and red when you miss, and every take gets a score.
When you finish, an AI coach looks at your accuracy and timing and tells you exactly what to fix, down to being consistently flat on a single note. There are 80 songs across four levels, each with a free tab page, a 6-stage curriculum, and a practice mode that slows any section to half speed and loops it until it clicks.
Decisions that mattered
- 01
Detection runs in the browser
Pitch and chord detection run on the Web Audio API on your own device, so feedback is instant and nothing has to round-trip to a server mid-song.
- 02
Free tools anyone can use
The tuner, the chord detector and every song's tab page work without an account. An account just saves your progress, library, and stats across devices.
- 03
Every song checked against the record
The first song data was AI-written, and a play-along tool that teaches the wrong riff is worse than none. In October 2026 every song was checked against published tabs and the original recordings, and 74 of the 80 were corrected.
- 04
Timed like the record
All 80 songs know how long every note lasts, read off published transcriptions of the record rather than guessed. Hear it first plays each riff in that rhythm before you try it, and the player gives you time to hold the long notes before it calls you late. It also handles lowered tunings and a capo, so a song can be played the way it was recorded.
Where it stands
- ▹Live and free at lark.coach.
- ▹A public tab page for every song at lark.coach/songs.
- ▹Installable on phones and laptops.
Work with me
If you run a local business and something about it still runs on paper, email me.
→ vinaybprojects@gmail.com