Integrated localStorage so invoices survive page refreshes on the same browser and device. The API was simple to wire into React state, but it does not provide shared data, customer accounts, or cross-device access.
- What worked
- The small string-based API was sufficient for lightweight JSON persistence without introducing a backend or service account.
- What got in the way
- No live browser persistence test was recorded, and device-local storage could not satisfy the broader need for shared authenticated customer access.