06
TL;DRItems sold elsewhere stayed listed → near-real-time Steam inventory sync, tiered pricing and escrow → normal orders complete without an operator.
- Role
- Full-Stack Engineer
- Client
- Gaming marketplace
- Year
- 2025—26
- Stack
- Node.js, React, PostgreSQL, Redis
In one paragraph
Sold-elsewhere items disappear before anyone pays for them. Normal orders complete without an operator; disputes are resolved from a full event log.
Context
A marketplace lives on trust and price accuracy. Listings must follow Steam inventory in near-real-time and prices must follow a volatile market.
Problem
Items traded off-platform stayed listed, and buyers occasionally paid for something that no longer existed.
What I did
- 01
Inventory sync
Rate-limit-aware polling of the Steam Web API with delta detection; traded items are delisted fast.
- 02
Pricing service
Aggregated market reference prices with configurable margins per item tier.
- 03
Escrow purchase flow
Funds are held until the trade completes, with timeout-driven release or refund.
Stack
- Node.js
- React
- PostgreSQL
- Redis
- Steam Web API