Series · 5 parts
Cuando started because my mom asked when the bus comes. Two years later it has maps we draw ourselves, route search, a news feed, and it's still growing.
This series tells it one piece at a time. Each part is dated to the moment it describes and written as things looked then, with a short note from September 2026 wherever hindsight changes the story.
Cuando is a bus app for Torrevieja, now on Google Play and the App Store. There was no data to start from, so we drew the network by hand: 163 stops, 16 lines, a stopwatch app and a lot of YAML. Here is how it works, and why a graph database lasted eight weeks.
Part 2
Every map decision in Cuando so far followed from how the map was billed. Six months of Mapbox, one week of vector tiles, a heatmap that decides how far you may zoom in, and, as of this week, a map we draw ourselves.
Part 3
Eighteen months of drawing our map as pictures, and why Cuando is moving to vector: one 58.67 MB file instead of 15 GB per theme, a Flutter renderer that crashed, and three map engines behind one view in the new apps.
For a year, route search in Cuando was one recursive SQL query. This autumn the app started calling it, and it started running out of memory. How route search in SQL works, why it blows up, and why, as of today, it runs in the Worker instead.
Part 5
Today, bus routes in Cuando started coming from Valhalla, fed with a GTFS timetable we generate ourselves. We have been publishing it, or trying to, every weekday since March, and until today nothing asked it for a bus. How to make GTFS when nobody publishes one, and how Valhalla loses every bus while every check stays green.
