Maps

Building Rally: A Live, Crowdsourced Court Map That Stays Honest

How I built Rally, a gamified, crowdsourced map of 1,450,000+ courts and fields across nine sports worldwide, using an Expo and React Native app on Supabase Postgres with PostGIS, a Cloudflare D1 edge replica for court reads, GPS proof-of-presence check-ins, and server-side-only scoring so the crowdsourced map stays trustworthy.