Otobees — internally developed as Zaggo / FirstGo — is a large, API-driven Flutter application that digitizes bus reservation and transport operations for the city of Zagazig, Egypt. It is Arabic-first at the product level: the app pins `Locale('ar', 'EG')`, uses RTL layout, shows all labels and validation messages in Arabic, and on wide desktop/web screens renders inside an iPhone 13 `DeviceFrame` mockup. The app implements four distinct user roles — passenger, driver, admin, and super-admin — each with its own `go_router` `StatefulShellRoute.indexedStack` shell and RBAC redirect guards. Passengers browse route lines, view line details, create/cancel bookings, subscribe to plans (immediate pay-now or deferred payment), and submit payments three ways: cash to an admin, cash to a driver, or electronic payment with a scanned receipt screenshot (`image_picker`). Drivers and admins confirm or reject those cash payments (with a mandatory rejection reason for drivers), review payment summaries and per-seat balance summaries, and admins additionally manage buses, drivers, passengers, stations, pickup points, route templates/sources, subscription types, approvals, and system settings. A super-admin manages admin accounts. The architecture is feature-first Clean Architecture (data → domain → presentation) with bloc/cubit state management over Freezed sealed states, `get_it` DI, Retrofit/Dio networking, and 90+ domain entities. Local caching is offline-first using Hive CE typed adapters with fallback only on connectivity errors, tokens live in `flutter_secure_storage`, Firebase Messaging delivers push notifications, and `local_auth` biometrics gate sensitive balance displays. Notable production touches include custom snackbar/dialog overlays, a reusable Zaggo design system, skeleton loading, infinite scroll pagination, and UTC-to-local time interceptor handling.