Zomee: a hyperlocal 10-minute delivery super-app built in Flutter on a FastAPI backend

Hyperlocal delivery is unforgiving. Customers expect sub-second app responsiveness and live tracking of an order that is promised in ten minutes; delivery partners and merchant outlets need to be coordinated in real time on the same order. The established delivery giants set the bar for native-quality UX, and a web-first approach would not reach it.

Building separate iOS and Android apps — for three personas — would have been cost-prohibitive for a startup. Zomee needed one mobile codebase that delivered native-smooth animation and interaction on both platforms, and a backend that could absorb thousands of concurrent order events without latency showing up in the app. ATS built both through our mobile engineering practice.

The mobile layer is one Flutter project with three persona entry points. The API layer is FastAPI, written async end to end so that order placement, assignment and status events do not block one another under load; PostgreSQL holds orders, catalogue, partners and merchants as the system of record. Firebase Firestore is the real-time fan-out layer — the apps subscribe to order documents and receive state changes without polling.

Google Maps SDK provides live tracking in the customer and partner apps; Stripe and Razorpay handle payments. Splitting transactional truth (PostgreSQL via FastAPI) from real-time distribution (Firestore) is what lets the platform keep API responses fast while every screen stays live. We used the same Flutter-plus-FastAPI pattern for ResqRoute, and it is a good fit for retail and quick-commerce products that need native apps on a startup timeline.