GTFS

GTFS is the most successful open standard in passenger transport, and it succeeded by being almost insultingly simple: a zip file of CSVs describing stops, routes, trips and stop times. It began as a collaboration between Google and Portland’s TriMet in 2006, is now stewarded by MobilityData, and is the reason a transit trip can be planned in any app anywhere without a bilateral integration.

• CSV in a zip - stops.txt, routes.txt, trips.txt, stop_times.txt, calendar.txt. No negotiation, no SDK, no onboarding.
• Schedule and Realtime are separate - the static feed describes the plan; GTFS Realtime, a protocol-buffer feed, describes what is actually happening.
• A ticketing extension exists - ticketing_identifiers.txt and ticketing_deep_links.txt carry the identifiers and links a third party needs to actually sell the journey, not just display it.
• Extensions and profiles are normal - GTFS-Fares v2, GTFS-Flex and others extend the core without breaking the base parsers.

What the evidence shows

Across the four State of Travel APIs Sector Reports, only three of forty newly researched organizations publish an open standard of any kind — and two of the three are railways publishing GTFS. Not one airline, hotel group, GDS or OTA appears in that column. In a sector organised around intermediation, the open-standard column belongs almost entirely to public transport.

The State of Canadian Travel APIs records the sharpest case. VIA Rail publishes GTFS Schedule plus the ticketing extension under the Open Government Licence – Canada, self-serve, with portable identifiers throughout — stop_id, four-letter station mnemonics, composite route identifiers, train numbers, ticketing_trip_id. It is the only genuinely open standard in the Canadian travel market.

It also carries a defect worth naming, because it makes the open licence unreliable. The Open Government Licence grants use of the feed for any lawful purpose including commercial, with attribution. The Site Terms of Use covering the same host prohibit use “for commercial purposes”. A business building on that feed has two published documents saying opposite things about whether it may. An open standard published under a self-contradicting licence is not, in practice, open — and this is the kind of gap that only surfaces when someone reads both documents rather than the badge.

Set against the rest of travel, GTFS demonstrates what the sector’s own standards bodies have not achieved: a shared vocabulary that competing organizations actually publish in common. In US travel, with three standards bodies in the market, the most-shared resource name across the entire corpus is spelled two different ways.