Product·7 min

Local-first health app architecture in Expo: Zustand, AsyncStorage, no backend

How we built VialBook with zero server infrastructure for the v0 release. Zustand plus app-local persistence, no account requirement, no VialBook cloud database.

Apr 28, 2026→

Product·5 min

Why free VialBook keeps 90 days of history · and the 3-compound cap

How we landed on the free-tier limits: 3 compounds and 90 days of history. The reasoning, the alternatives we rejected, and why safety features never get paywalled.

Apr 24, 2026→

Product·5 min

Notifications that actually fire: the #1 thing every other app gets wrong

Why local notifications beat push servers for health reminders, and how VialBook engineers reliability · 50 firings, 0 drops, every release.

Apr 22, 2026→