Product case study · Independent product · Chrome Web Store

Chotu Pet

A pixel companion that lives on every page you visit and evolves through five stages based on your browsing — a Manifest V3 Chrome extension.

Role: Solo: design, extension, motion
When: Live
Links: Chrome Web Store Source

Browsing activity
Evolution rules
Persisted state
Page overlay

System flow

The problem

A playground for the hard parts of browser extensions: one character whose state has to persist across every tab, rendered on top of pages the extension doesn’t control.

What I did

Designed and built the extension end to end
Motion design across WebGL, CSS and spring physics
Published on the Chrome Web Store

Architecture

Manifest V3 extension built with CRXJS and Vite, with HMR during development
Pet state persisted across tabs with Zustand
Three.js aura, Framer Motion idle physics, CSS Houdini particle effects
Hybrid audio: Web Audio API plus an MP3 sound pack
CSS cascade layers and @scope to avoid colliding with host-page styles

Stack

React 19
TypeScript
Chrome MV3
Three.js
Zustand
Web Audio
Vitest
Playwright