We are looking for an experienced Python backend engineer to build a real-time engine for a public bus pilot project, with potential to scale to a full city network. The engine must: - Collect GPS positions from buses continuously - Clean and project these positions onto GTFS routes (shapes) - Calculate real average speed and ETA for each stop - Generate a single GTFS-Realtime feed (TripUpdates + VehiclePositions) - Publish this feed via a stable HTTP URL for OpenTripPlanner (OTP) and Google Maps - Update the feed every 3–10 seconds - Automatically detect and correct GPS anomalies to prevent incorrect ETA displays **Technical requirements / technologies:** - **Python backend development**, experience in real-time data processing - **Redis**: in-memory database for storing real-time bus states (position, speed, ETA, status) - **PostgreSQL**: optional but recommended for storing historical data for analysis and statistics - **GTFS / GTFS-Realtime / OpenTripPlanner** experience - **Geolocation / GPS data processing** - **API frameworks**: FastAPI or Flask - Ability to handle scalability from **10 buses (pilot) → 100+ buses → multiple lines/cities** - Knowledge of scheduling / timers for high-frequency updates **Deliverables:** - Fully working real-time engine with GTFS-Realtime feed - Documentation for setup and scaling - Optional: example of historical data integration for analytics Please provide references or examples of similar projects you have completed. Only experienced engineers with relevant skills should apply.