Shotgun

Every break, hundreds of Cal Poly students drive the 101 alone while the Facebook rideshare group fills up with unsearchable posts like “heading to san jose friday, 2 spots, gas $$”, so we built Shotgun, a carpool board that turns those paragraphs into structured fields you can actually query: origin, destination, time, seats, and a suggested gas split from distance and MPG. Signup is restricted to @calpoly.edu addresses. We built it with Expo and React Native on Supabase, using a Geoapify Edge Function for place search and routing, Apple Maps for the route preview, and Row Level Security so contact details stay scoped to people actually on a trip. The hardest calls were scope ones: we cut payments entirely, since carpooling stays legal and insurance-safe precisely because drivers split costs rather than earn income, and we left money off-platform. The big lesson was that we can’t beat the Facebook group on network effects, but turning a text feed into queryable data is a real advantage, and a driver can post a ride here and drop the link straight into the group, making it a distribution channel instead of a competitor.