QRChing.

QRChing arrived as a freelance brief and got treated like a product: Isfan wrote the technical spec first — scope, API contract, sprint plan — then built it as a Melos monorepo with its own design-system package.

The app itself: camera-first QR scanning on mobile_scanner, two raffle engines — Classic and Dynamic — Riverpod 2 state, go_router navigation, Dio + Retrofit networking. Delivered to TestFlight. The spec written in June 2025 still describes the system that shipped — that's the point of writing it first.