It still exists and powers millions of transit rider trips every day all around the world in Seattle, Washington DC, New York City, Poznan Poland, Buenos Aires Argentina, Adelaide Australia, and who knows where else.

If you’re interested in hacking on something like Citymapper, or setting up an OBA server for your own city, you can find everything you need on our GitHub organization: https://github.com/OneBusAway

That includes docker images, an iOS app and a trip planner framework, android app, Sveltekit web app, and even a next generation OBA server written in Go.

As far as the data to power this, you can get GTFS for every US transit agency from https://mobilitydatabase.org/

(nb I’ve been involved in the OBA project since 2012)

Performance wasn't great since everything had to run locally and do network roundtrips, but it found routes in my hometown that Google Maps didn't show. Pretty cool discovering hidden connections in the transit network and being able to customize your own params (https://github.com/denysvitali/optitravel/blob/master/src/ma...)

It supports many features and has a very active developer community.

Whilst HN is on the case, does anyone know of an API (inside Rail Data Marketplace or elsewhere) that acts as a journey planner for UK national rail, i.e. you can input source + destination stations and it will output journey options?