About the project
SageTuner is a free, offline guitar tuner I designed and built with AI assistance after getting tired of my iPhone constantly offloading my previous tuner. What started as a small personal frustration became a lightweight Progressive Web App for guitar, bass and ukulele, with a built-in metronome, no accounts and no unnecessary downloads.
- Role & Context
- Solo Product Designer · 1 evening · 2026
- Toolbox
- Figma · Codex · Claude · HTML · CSS · JavaScript · Web Audio API
The making of SageTuner
I have my iPhone set to automatically offload apps I don't use frequently to save storage. Unfortunately, my guitar tuner is often one of them.
After repeatedly having to download it again, I decided to build my own.
I spent about an hour and a half after dinner playing guitar while working with AI to bring my designs to life. I'd play, test the tuner, adjust the interface, and go back to playing. It was a surprisingly enjoyable and almost meditative process.
The result
SageTuner (opens in a new tab) is a lightweight Progressive Web App that lives on my home screen, works offline, and requires no account. It uses a color gradient for immediate visual feedback, alongside a more precise scale to show how far a note is from being in tune.
It takes up just 172 KB, compared to the 2.5 GB occupied by my previous tuner.
It was a small problem that turned into a fun experiment and, ultimately, a tool I now use myself.
I also made it open source, so anyone can try it, explore the code, or build on it.