Overview
Hand Me Downs is a mobile marketplace for secondhand goods — the kind of two-sided product where nothing works until both sides do. Sellers need a fast, low-friction way to list; buyers need to browse, trust, and transact. I designed and built the whole thing: the iOS app, the Postgres data model, the auth and storage, and the analytics that tell me whether the marketplace is actually breathing.
What I built
- A Capacitor iOS app — listing creation with photos, browse/search, and user profiles.
- A Supabase backend: Postgres schema for users, listings and the marketplace funnel, with row-level security and image storage.
- A "Marketplace Health" analytics dashboard in Metabase — 26 SQL-native cards across Growth, Liquidity & Funnel, Supply & Pricing, and two-sided Engagement, fed by a strictly read-only role so reporting can never touch production data.
- Reproducible dashboard tooling — every query is version-controlled and the whole dashboard rebuilds from code.
Why it matters
Marketplaces live and die on liquidity, and you can't improve what you can't see. Rather than guess, I instrumented the funnel end to end — signups, listings over time, the buyer/seller balance — so product decisions ride on honest numbers, not vibes. The dashboard scales automatically as the marketplace grows.
Screens
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Screenshot placeholders — drop real images into assets/hand-me-downs/ and swap these in.