ML.
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Software Engineer @ UJET · ex-Founder/CTO · Seoul, open to global roles

MARTIAN
LEE.

I move fast with AI — and keep the decisions that matter human.

↓ View projectsPostsCV ↗GitHub ↗
01 — ProjectsAll projects →
Hanji.md

Hanji.md

macOS App

A native macOS markdown editor for plain-file vaults, built on SwiftUI and TextKit 2 with a Swift extension SDK. Incremental Live Preview keeps a keystroke in a 4,000-line note at about 15 ms, with performance budgets checked in CI. Local-first, MIT licensed.

Mo

More Munch

Web Service

A lunch-recommendation service for office workers. It auto-collects nearby restaurants (discoverable via the OpenClaw skill-optimized API) and suggests a fresh lunch every day based on your visit history and ratings.

CheerCat

CheerCat

Mobile App

A daily journaling app that builds the habit of praising yourself every day — a small ritual for a positive mindset.

Earth Invaders

Earth Invaders

Arcade Game

A Phaser3 arcade shooter. Fend off the aliens invading Earth, classic arcade style.

02 — Recent postsAll posts →

I take large codebases apart and write down how they actually work.

2026년 10월 7일 · 30 min read · game-modding / minecraft

Inside the Bridge That Runs Minecraft in Elden Ring: How Do Two Games Share One Frame?

Since late September, "passthrough modding", which runs two games at once and merges them into one, has been everywhere. This post reads minecraft-crossover-bridge, the one implementation with public code, and walks through what its shared-memory protocol, depth-tested compositing, terrain raycasts and hidden stand-in character each solve, and what the projects built on it changed.

2026년 9월 29일 · 16 min read · ruby / rails

What Does Active Record Build on Every Request? Measured the Same Way as Sequelize and GORM

The last post concluded that Ruby is not slow and that most of a Rails request is Active Record. This one compares what Active Record does per request with Sequelize and GORM, by reading the source and measuring. Most of the cost comes from a has_and_belongs_to_many preload that turns every join row into a full record, and there is a way to cut it sharply while keeping the same SQL.

Where Does One Rails Request Spend Its CPU? HTTP, Routing, Database and ORM, Measured Apart2026년 9월 28일
Archify dissected: what changes when the agent writes an IR instead of drawing the diagram?2026년 9월 12일
DeepSeek Harness Hands-On: Dumping the Boot Tree and Swapping Rows With Patches2026년 9월 9일
03 — ExperienceCV ↗

UJET — Software Engineer 2

UJET is AI-Powered Cloud Contact Center Platform for Premium CX · Rails · GCP · Node.js · TypeScript · Kubernetes

2024 - Present

TomorrowUse — Co-founder / CTO

Climate-tech startup (product: Stepping). Sole engineer on a three-person founding team; built carbon-measurement and offset products end-to-end: app, infra, and CI/CD. · Next.js · React · Nest.js · PostgreSQL · AWS · 0to1

2021 - 2023

Miso — Frontend Developer

South Korea's leading home services platform. Responsible for client app maintenance and back-office development to improve CX operations. · React · React Native · Redux · TypeScript

2020 - 2021
Open to senior / staff engineering roles — globally.
Email ↗GitHub ↗LinkedIn ↗