Logistics & Mobility
Expo Delivery & Driver Platform
Real-time fleet coordination for enterprise logistics
Lead full-stack architect — mobile, backend, and AWS infrastructure · 9 months · national logistics rollout
Challenge
A national courier needed unified driver and customer apps with offline-first delivery tracking, push notifications, and sub-second location updates across 2,000+ active drivers.
Solution
Architected a React Native (Expo) monorepo with shared business logic, WebSocket-backed live tracking, background geolocation, and a NestJS event-sourced backend on AWS Lambda with SQS fan-out for order state machines.
The problem
Drivers used fragmented tools. Dispatchers lacked a single source of truth for order state. ETA predictions drifted because location updates were batched and lossy on poor networks.
Architecture
Expo monorepo for driver and customer apps with shared TypeScript domain models. NestJS services on Lambda consumed SQS events for order lifecycle transitions. Redis held live driver positions; PostgreSQL remained the system of record with optimistic concurrency on state changes.
What I owned
End-to-end delivery: mobile offline queues, WebSocket fan-out design, CI/CD for OTA updates, and the saga-style order processor that kept partial failures recoverable without manual ops intervention.
Impact
- Reduced delivery ETA errors by 34%
- 99.7% crash-free sessions across iOS & Android
- Onboarded 2,000+ drivers in 6 weeks
Lessons learned
- Offline-first mobile is non-negotiable for field workforces.
- Event sourcing lightens debugging when 2,000 drivers mutate state concurrently.
- Invest in observability early — ETA accuracy was a metrics problem before it was an ML problem.