An unofficial statistics site for the Berlin Mini-Marathon, the 4.2195 km school race held alongside the Berlin Marathon. It turns a raw finish list of more than 10,000 children into something kids, their families and teachers enjoy. Parents open a shared link on their phone and find their child in seconds. They come away with a story, not just a time: "faster than 73% of girls in the group", "beat the school median by a minute", or "fastest of the whole race".
Key features:- Runner cards show the place in the group and in the whole field, how the child compares with classmates and the school, a "ghost race" against medians and winners, and fun facts.
- Earlier starts: children are linked across nine editions (2016-2026) using name, gender and school rules, so families can see progress year by year and race their earlier self on the interactive course map.
- Fair school rankings: team top-5, median times with minimum group sizes, turnout and finish rate, so small and large schools can be compared fairly. Free-text school names from older years are matched to the current list using the names and where the same kids ran the following year.
- "What if" tools show where a time would place in other groups or in earlier editions.
- Race replay on the real course map, simulated from finish times with a documented pace model and clearly labelled as a simulation.
- School recaps in the style of a sports commentator, written by Claude from a computed fact card. A script checks every number and name against that card before publishing.
The site is designed with privacy and kindness in mind:- Surnames are reduced to an initial, and individual dots on charts are anonymous.
- Runners without a finish time are never suggested in search.
- Weak results are never highlighted.
It runs in English, Polish, and German, best UX on desktop, but works with mobile in mind. It is a static site with no backend and no third-party requests (self-hosted fonts for GDPR). It was built with Claude Code, from data analysis and data cleaning to the front end and deployment.
