Timetable application

The challenge

Koleje Małopolski operates dozens of bus and train routes across the entire Małopolska region, but their schedule data existed only in raw GTFS format, a technical standard passengers cannot directly interact with. The solution needed to be embedded inside their existing website without touching the host page, and had to support multi-modal connection search across hundreds of stops spanning two transport types.

The solution

A Flutter web widget with a bootstrap configuration system was built, allowing the client to embed the entire application by adding a single script tag and an empty container to their existing page. On the backend, a NestJS service handles nightly GTFS ingestion, checking for dataset changes via hash comparison and refreshing the database when updates are detected. The core of the connection search is a custom implementation of the RAPTOR algorithm, built from scratch based on the original Microsoft Research paper, extended to support multiple itineraries across mixed bus and train routes. A GraphQL API serves the frontend, background workers handle PDF generation for printable schedules, and an admin panel allows the client to configure route colors, highlighted stops, and upload GTFS data manually when needed.