From Vibe-Coding to Reality: Building MarvinSync

If you saw my posts back in February on LinkedIn and Mastodon, you know I’ve been deep in a Cursor session. I promised to pull back the curtain on how MarvinSync—my new macOS utility for syncing local music to Android—came to life through the lens of AI-assisted development. Before we get to the binaries (which are coming soon, I promise!), I want to share the vibe-coding post-mortem of how the first version actually took shape. If you want to follow along with the code as I describe it, the full project is already live on Codeberg. What is MarvinSync? (And why Vibe-Code it?) MarvinSync is a utility designed for a specific niche: people who still believe in local media ownership. It bridges the gap between a curated macOS music library and an Android device. No streaming, no cloud—just your folders, your metadata, and a clean sync via ADB (Android Debug Bridge). But there’s a meta-story here. As an Android GDE, I spend my life deep in Kotlin, Compose, and Kotlin Multiplatform. Naturall