How I built Google Drive sync without a backend (and the 3 bugs that almost broke me) (opens in new tab)

When I started building PenPage — a privacy-first note app that stores everything in IndexedDB — I made one assumption that cost me three weeks of debugging: "Google Drive sync will be the easy part." It wasn't. Here's what I learned building a sync engine entirely in the browser, with no backend server. ## The core idea: one file to rule them all Instead of syncing every note file individually, I built around a single sync.json that stores all metadata: ppage-app/ ├── sync.json ← the source ...