Jang-Ho Hwang

Even on days off, I'm usually building something.

Things I've open-sourced

• Vimdow A macOS window manager driven by Vim keys: move, resize, and snap windows with hjkl, counts, and undo. Swift and AppKit.
• Orrery Saju, Zi Wei Dou Shu, and Western natal charts, calculated entirely in the browser with no server. The engine is also on npm. React and TypeScript.
• Sonica Turns an audio file into a visualizer video: FFT analysis, WGSL shaders on the GPU, and an MP4 at any resolution or aspect ratio. Rust with wgpu, ffmpeg.
• Zitat Clips part of a YouTube video, transcribes it with Whisper, translates the subtitles with Claude, and burns them in, with a review step before the final render. Python.

What I'm building at work these days

• BizRouter An LLM gateway for Korean companies: one API key for a dozen AI providers, billed in won. I built everything from the Rust proxy to the admin console. These days new people are working on it, so my commits have slowed down.
• Wrks AI Image An image generator that doesn't require prompt skills. Pick a purpose, type in plain Korean, and you get an image.
• Wrks AI Video Describe a scene in Korean and get a short video, sound included.
• Wrks AI Notes Transcribes meeting recordings by speaker and pulls out decisions and action items.

The last three I build alone, from planning and design through development, operations, and infrastructure. In between, I put newly released models on H100s to see what they can do.

Things I build for myself

• Anvil A dictation, TTS, and chat server that runs on my Mac with no cloud. One shortcut from the menu bar for voice input anywhere. Python with MLX, FastAPI, React.
• Morax An iOS app that turns spoken thoughts into tasks, events, and notes. Audio is transcribed on the device and never leaves it. SwiftUI, Bun with Hono, SQLite.
• Burrow A messenger for iOS and macOS made for a handful of close friends. Passkey sign-in, photos, videos, and calls. SwiftUI, Rust with PostgreSQL, WebSocket.
• Butter A personal app for habits, notes, and photos. The server accepts client certificates only. Rust with PostgreSQL, Flutter.

My older iOS apps and Mouton Journal are on the works page.

Recent posts (in Korean)

1. 2025.06.29 술 취한 Claude Code 길들이기
2. 2025.06.04 로컬 AI 모델의 황금기
3. 2025.06.01 LLM 시대에도 GUI는 사라지지 않는다
4. 2025.05.30 Python 3.14 개발자 친화적 업데이트들
5. 2025.05.27 바이브 코딩을 무시하는 시니어들에게
6. 2022.06.18 체지방 9kg 감량과 함께 찾아온 변화들

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