System Design: Real-Time Delivery Logistics and Route Visualization Platform

Context

Design a platform that allows dispatchers and end customers to view couriers' real-time positions and routes for millions of deliveries per day. The system must ingest GPS data from courier apps, compute and render routes, stream live updates to web/mobile clients, and support historical route queries.

Requirements

1. Functional
   • Real-time tracking of couriers on a map (sub-second to a few seconds latency).
   • Route computation with ETAs; dynamic re-routing with traffic.
   • Live and historical route visualization for dispatchers and customers.
   • Order lifecycle: create order, assign courier, update status, complete.
   • APIs for orders, assignments, location updates, live/historical route queries.
2. Non-functional
   • Scale to millions of deliveries/day; hundreds of thousands of concurrent couriers.
   • Low-latency updates; high availability; multi-AZ deployment.
   • Event-driven architecture with durable streams.
   • Offline handling for mobile; privacy controls; failure recovery.
   • Monitoring, alerting, and capacity estimates (compute, storage, bandwidth).

Deliverables

Detail: service architecture, data model, GPS ingestion pipeline, route computation, map rendering, event streaming, scalability plan, latency vs. consistency trade-offs, offline handling, privacy controls, failure recovery, APIs (orders, assignments, locations, queries), capacity/storage estimates, and monitoring/alerting.