Software engineer · real-time marketplace & backend systems

Xinghan Yin尹星寒

AI writes the code. I own the system.

I'm the co-founder and lead engineer of GGBOYS, a live real-time digital-asset marketplace. It plugs into Steam's real trading system, holds users' actual money, and runs across a web app, a mobile app, and a browser extension — all on a backend and infrastructure I built and run myself.

AI has made code cheap — as much of it as you want. But cheap code doesn't make a reliable system cheap. A system that handles real money, talks to a real exchange, and can never go down — getting it built and keeping it running was never about one piece of code or one agent. It comes down to one person holding the whole thing in their hands: setting the direction, setting the bar, deciding what to build and what never to touch, signing off on every decision and every dollar. That's the seat AI amplifies but can't replace — it writes for me, reviews for me, runs for me, but it can't hold the whole picture, and it can't be the one who answers when something breaks.

• ggboys.com — a live real-time digital-asset marketplace: trading, orders, wallet, rentals, market data, and an escrow/ledger/risk admin, plus a Nuxt site, a Chrome extension, and a Flutter app.
• CiteTrail — an AI research tool with a deterministic firewall that checks every citation against six academic databases and drops the ones it can't verify. Live at citetrail.com.
• OurRPG — a multiplayer AI tabletop game where the agent that knows the plot has no way to reach the text players read. Live at ourrpg.com.
• MemTree — the structured memory my coding agents read before they touch a file: per-file relations, known traps, and what's gone stale.