Overview
Built a live e-commerce storefront that consumes the product catalog in real time from an iOS inventory app through Firestore onSnapshot listeners. Implemented a reservation-based checkout flow and atomic Firestore transactions for stock decrement/restore, preventing overselling even under concurrent purchases. Any product added or updated from the iOS app appears on the storefront instantly without redeployment. Deployed on Vercel with Astro for fast static delivery and client-side Firebase SDK for real-time reactivity.