The problem
Buying gold person to person in the Philippines runs on trust and screenshots. Buyers cannot check today's price against an offer or tell a verified seller from a stranger, and the shop owner had no channel of her own outside social media.
What was built
A marketplace with live gold prices and price alerts, account verification with an ID check and a face re-check, listings with offers and a trade flow that only releases when both sides confirm, and an Official Shop where the owner sells her own pieces: paid in store, by GCash or bank receipt confirmed by staff, or cash at a meet-up. Sellers pay a 3% fee on completed trades from their own account page; an overdue fee pauses new listings but never a delivery already in motion. Staff roles require two-factor sign-in. Installable as an Android app as well as the website.
The engineering decision
Every outside provider that is still simulated (SMS codes, identity checks, payments) is labelled as test mode on screen, by the owner's choice, rather than faked as working. Payment details live only in the database and appear only on the buyer's own order page, never in the code. It began as a React Native (Expo) app prototype and grew into the web marketplace.
How I built it
- Languages
- TypeScriptSQLCSS
- Frameworks & libraries
- Next.js 16React 19Prisma 7 ORMBetter Auth (two-factor for staff)
- Apps & tools
- Claude Code (AI pair-programming)Git & GitHubDocker (local PostgreSQL)Playwright (end-to-end tests)Bubblewrap, JDK 17 and Android SDK (Android app)Expo / React Native (first prototype)
- Hosting & data
- VercelPostgreSQL on Neon (Singapore region)Android APK
- 01
Prototype
Started as a React Native app in Expo to test the gold-trading flow, then moved to the web so one build serves every phone.
- 02
Marketplace core
Live gold prices and alerts, listings, offers and a trade that releases only when both sides confirm.
- 03
Trust and safety
ID verification with a face re-check, two-factor sign-in for staff, and every still-simulated provider labelled as test mode on screen.
- 04
Official Shop and fees
The owner's own shop with in-store, GCash or bank receipt and meet-up payments confirmed by staff, and a 3% seller fee on completed trades.
- 05
Android app
Packaged with Bubblewrap as a signed Android app that opens the live site full screen, downloadable from the site itself.
Next plate
AI UGC Ad LibraryOngoing library of AI-generated UGC-style product and affiliate video ads produced entirely in-house across Facebook, Instagram, TikTok and YouTube.