GTFS (General Transit Feed Specification)

GTFS, the General Transit Feed Specification, is a zip file of plain comma-separated text files describing a transit system: agency.txt, stops.txt, routes.txt, trips.txt and stop_times.txt. It is deliberately dull, and it is the reason a journey planner can show you a bus at all. Written in the mid-2000s so Google Maps could display transit, it is now stewarded by the non-profit MobilityData and used by thousands of agencies.

Because the format is open, publishing one feed hands every app the same timetable at once — a cheap way to appear in the tools riders already use, and a form of open data that survives its own budget. Researchers in Nairobi rode roughly 130 informal matatu routes with GPS-equipped phones and published the result as GTFS, putting an informal transit system into consumer journey planners in 2014. The grant ended; the dataset did not.

The honest caveat is that GTFS describes a timetable, not reality. Live vehicle positions come from GTFS-Realtime, a separate feed most cities publish worse, later or not at all — and a published feed says nothing about whether anyone maintains it. Delhi has offered open GTFS since 2018, yet reporting in 2026 found GPS units offline, route changes missing from the static files and no stop showing live arrivals. In Bengaluru, buses go missing from the live feed while developers maintain an unofficial GTFS scraped out of the operator's own app.