JK Jung · Staff Software Engineer · Los Angeles
Twenty years of production systems — MMO-scale databases, global commerce platforms, and AI-native SaaS. Lately: four live consumer products and an AI-operated ERP, each designed, built, and operated end to end.
01 · Selected Work
Everything below was designed, built, deployed, and operated end to end — architecture, backend, frontend, mobile, infra, and billing included.
AI fashion design studio — from text prompt to runway video.
A production SaaS where designers generate garment designs from text or sketches, composite virtual try-ons onto custom AI models, and animate the results into 1080p fashion film. Solo-built and operated: async FastAPI backend, Next.js frontend, Stripe metered billing, and multi-provider AI routing across Gemini, OpenAI, and Kling.
The alarm you can only silence by spelling the word correctly.
A vocabulary trainer fused with an alarm clock, live on the App Store in 8 languages. SM-2 spaced repetition schedules every word; Gemini powers Smart Scan (photograph a word list, import it all), AI definitions, and an adaptive placement quiz that builds a personalized starter pack.
Real-time PvP number baseball with server-authoritative Elo — and provable anti-cheat.
A real-time, turn-based PvP deduction game on the App Store. Per-format Elo ratings, an 8-tier ladder, a credits economy, and a 1,000-bot opponent pool — with every rating, credit, and match result settled server-side, and an SHA-256 commit-reveal scheme that makes cheating provable.
Up to four players race the same board in real time — coordinated by Redis, settled by the server.
A real-time multiplayer sliding-puzzle race on the App Store: 2–4 players, identical boards, combo attacks that disrupt opponents. A TypeScript backend owns matchmaking, Glicko ratings, and the credit economy, with Redis distributed locks and cross-node Socket.IO fanout keeping multi-instance state honest.
From a text prompt to a production-ready 3D film set — deployed straight into Unreal Engine 5.
An AI-orchestrated virtual production pipeline: Claude lays out the scene as a validated spec, Rodin Gen-2 generates the meshes, FLUX and Gemini handle reference imagery, and an 871-line UE5 Python watcher places, textures, and lights the whole set — with natural-language edits applied in under a second.
RGB
DEPTH
NORMALS
ALBEDOTurn any Unreal Engine 5 scene into pixel-aligned, ML-ready training data.
A synthetic-data pipeline running inside UE5's embedded Python: a synchronized four-camera rig captures RGB, float16 depth, world-space normals, and albedo with zero pose drift, plus per-frame intrinsics and 2D/3D bounding boxes — ingested into PostGIS and explored in a Next.js viewer with 3D trajectory playback.
An AI-operated commerce platform running a global fashion business — built as the first engineer.
The operating system of a global commerce company spanning the U.S., Korea, and China: a full ERP, sync workers federating 6+ marketplaces, SKU-level profitability intelligence, and AI agents that draft reorders and generate content. Built from zero as founding engineer. Name withheld — it runs a real company.
Your closet, digitized — and an AI that knows if it's worth buying.
Currently building: photograph your clothes and vision models digitize the closet; a fashion-embedding engine then scores any new piece for novelty and compatibility against what you already own. Outfit ideas, weather-aware picks, packing plans. In private beta — more soon.
02 · Why me
Not demos — billed products. Multi-provider model routing (Gemini, GPT, Kling) inside a live SaaS that users pay for monthly, AI agents with human-approval guardrails running a real company's operations, and Claude-orchestrated 3D pipelines in open source.
Before AI, the training ground was live gaming infrastructure: 12 primary MySQL databases, 100M+ rows per table, 500GB monthly growth, failover cut from 10 minutes to under 60 seconds.
First engineer at two companies in a row. ERP systems that replaced paper, marketplaces that launched in new countries, engineering teams hired and mentored — and the architecture decisions that let all of it keep shipping.
03 · Capabilities
Every item below appears somewhere in the projects above — nothing aspirational.
04 · Contact
I'm based in Los Angeles and open to staff-level engineering and founding-engineer roles. The fastest way to evaluate me is to use the products above — then let's talk.
