I shipped a 100% offline personal finance app as a solo dev — here's the full stack

After months of building in evenings and weekends, I shipped Budgetify to the Google Play Store last week. It's a personal finance tracker built around one hard constraint: no servers, no accounts, no data ever leaving your device (unless you explicitly back it up). This post is about the technical decisions that made that possible — and the tricky parts I didn't expect. Why build another finance app? Every finance app I tried either required an account, synced data to their servers by default, or locked basic features (like recurring transactions) behind $10+/month subscriptions. I wanted something that worked like a proper offline-first tool — fast, private, yours. So I built it. Stack React Native + Expo (managed workflow) Expo Router (file-based routing — app/(tabs)/ and app/(screen)/ ) SQLite — all data, all local, expo-sqlite RevenueCat — subscription & IAP management Google AdMob — free tier monetization EAS (Expo Application Services) — builds & Play Store deployment GitHub Act