John Choi 최요한
On my journey, developed real-world communities together at Niantic and scaled semantic relevance at Reddit.
Where I worked, what I built, and when.
-
Senior Machine Learning Engineer
- Delivered Milvus-backed semantic retrieval on Reddit Feeds, improving new-user activation and retention (~1M+ DAU) while meeting strict latency and availability SLOs.
- Launched SEO search experiences in collaboration with 3 teams, driving an increase of ~500k DAU.
- Reduced ML server costs ~$1.5M/year with a distributed caching solution and improved search resilience with adaptive traffic shedding across high-QPS endpoints.
Vector DB Infrastructure Embedding Retrieval Optimization -
Software Engineer III
- Led creator payouts and reconciliation, distributing multi-million-dollar payouts across 30+ countries and 25+ currencies.
- Built payment webhook and verification services for Apple, Google, and Stripe notifications across purchase, refund, fraud, and reconciliation flows.
- Built automated E2E testing suite across Payments critical paths, catching release-blocking regressions before production launch.
Blockchain Kubernetes Vendor KYC -
Software Engineer
- Rebuilt Pokemon Go quest and rewards flows, reducing high-traffic quest page load time by 25%.
- Shipped guest-account onboarding that improved post-launch player retention by 30%.
- Partnered with AR/R&D teams on Pokestop 3D scan uploads to support AR mapping platform development.
GCS Unity Performance Tuning GeoSpatial Modeling