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Chen Yang

Projects

Things I've built and worked on.

BikeShare

May 2026 – Present
  • Built a full-stack peer-to-peer rental marketplace with JWT auth and role-based access across 3 user roles, 12 pages, and ~30 REST endpoints, letting students list, search, and rent bikes, scooters, and skateboards.
  • Implemented indexed geospatial radius search in PostGIS over a GiST spatial index, with radius, price, type, rating, and availability filters.
  • Engineered a privacy layer that exposes only approximate pickup locations until a booking is accepted.
  • Engineered a booking engine that prevents double-booking under concurrency, combining interval-overlap checks with pessimistic row-level locking to serialize simultaneous acceptances, enforced by a state machine and integration tests.
  • FastAPI
  • PostgreSQL/PostGIS
  • React
  • TypeScript
  • SQLAlchemy
GitHub

FacetForge

June 2026 – July 2026
  • Built an end-to-end CLI that transforms unstructured Shopify catalog data into queryable product facets using deterministic extraction, embeddings, reranking, LLM classification, and computer vision with confidence-based abstention.
  • Designed a resumable, cost-aware inference pipeline with closed vocabularies, Zod schema validation, granular caching, concurrency controls, exponential backoff, provenance tracking, and offline provider fallbacks.
  • Implemented automated taxonomy discovery, text-vision fusion, human correction workflows, Shopify metafield exports, and HTML/CSV coverage reports, validated by a deterministic test suite.
  • TypeScript
  • Node.js
  • LLMs
  • Embeddings
  • OpenAI
  • Zod
GitHub

Boiler Bites

July 2025 – September 2025
  • Built a Purdue dining hall macro tracker that lets users log meals, set macro goals, and view daily calorie and macro totals.
  • Automated daily ingestion of Purdue dining court menus via Vercel Cron so menu data stays current without manual updates.
  • Hardened production with Sentry error tracking and structured logging to shorten debugging of failed ingestion runs.
  • Next.js
  • PostgreSQL
  • Prisma
  • NextAuth
  • Vercel
GitHub

Poker AI Bot

March 2025 – May 2025
  • Built an LSTM-based poker agent using PyTorch and self-play reinforcement learning, achieving a stable positive win rate against baseline opponents.
  • Python
  • PyTorch
  • Reinforcement Learning
GitHub