TrackTheBus
A real-time public transit tracking platform providing live vehicle positions, schedules, and community features for Sofia's 2,500+ transit vehicles.
The Challenge
Sofia's public transit system serves over 1.3 million residents with a network of buses, trams, trolleys, and metros. However, commuters had limited access to real-time information about vehicle locations and arrival times, leading to uncertainty and frustration.
In late 2025, SofiaTraffic made a pivotal decision to open their GTFS data to the public. This gave us the opportunity we had been waiting for—a chance to build something meaningful for the city we live in.
We rapidly built TrackTheBus to transform raw GTFS data into actionable information, helping riders make informed decisions about their daily commutes with real-time tracking and community features.
Real-time Map Interface
Interactive map showing live vehicle positions
What we built
A comprehensive feature set designed to serve daily commuters with real-time, accurate transit information.
Real-time Vehicle Tracking
Sub-second updates via WebSocket connections showing live positions of all transit vehicles on an interactive map.
Schedule & Arrival Predictions
Complete timetable access with arrival time predictions that account for real-time delays and traffic conditions.
Favorite Stops
Save frequently used stops for quick access to departures from home, work, or other common locations.
Route Planning
Find optimal routes between any two points using the transit network with transfer suggestions.
Community Reports
Users can report issues, share observations, and engage in discussions about transit service quality.
Multi-city Support
Scalable architecture supporting any GTFS-compliant transit system. Currently serving Sofia with more cities planned.
Built with Modern Stack
We chose technologies that prioritize performance, developer experience, and cross-platform compatibility. The entire stack is designed for real-time data processing and seamless mobile deployment.
Frontend
Backend
Data
Infrastructure
System Architecture
Challenges & Solutions
Technical obstacles we overcame during development and the approaches we took.
Real-time Data at Scale
Processing thousands of vehicle position updates per second while maintaining low latency for all connected clients.
Implemented Redis pub/sub for message distribution and geographic clustering to reduce unnecessary updates based on user viewport.
GTFS Data Complexity
Handling the complexity of transit schedules with service exceptions, calendar variations, and shape geometries.
Built a robust GTFS parser with preprocessing pipeline that normalizes data and pre-computes common queries.
Cross-platform Consistency
Delivering a consistent user experience across web browsers, iOS, and Android with native-like performance.
Used Ionic with Capacitor to share a single Angular codebase while leveraging native APIs for geolocation and notifications.
Project Timeline
From concept to production in 12 months.
GTFS Data Opens
SofiaTraffic releases public GTFS feed, enabling real-time transit tracking.
Rapid Prototyping
Built initial proof-of-concept with map integration and basic vehicle tracking.
Public Beta
Launched beta version with WebSocket real-time updates and mobile apps.
Community Features
Added user accounts, favorites, reporting, and discussion capabilities.
Production Launch
Full production release with 99.9% uptime SLA and performance optimizations.
Expansion
Adding new cities and features based on user feedback and partnerships.
Want to build something similar?
Whether you're a transit authority, city government, or private operator, we can help you implement real-time tracking solutions for your network.