About Me
Zac Ji
Senior iOS & Indie Developer
Hi! I am Zac (Hongbo Ji). I have 10+ years of professional iOS native engineering experience, focusing primarily on the Apple ecosystem (iOS, macOS, watchOS, tvOS, visionOS), alongside cross-stack skills in Android, Flutter, and modern Web engineering (Astro/Vue/CSS).
Being fluent in Chinese, English, and Korean enables me to easily localize, design, and ship my apps to global markets. Currently, I am dedicated to creating streaming, utility, and AI applications, aiming to craft highly fluid, thoughtfully designed software for users worldwide.
iOS Core
- Swift & SwiftUI
- UIKit & Auto Layout
- Structured Concurrency
- Combine & Reactive Programming
- SwiftData & SQLite Storage
Performance
- Xcode Instruments Diagnostics
- Memory Leak Debugging
- App Launch Speed Tuning
- Core Animation Frame Rates
- Modular & Native Architecture
Engineering
- Astro / Vue / CSS Modules
- Node.js / Cloudflare Workers
- Git & GitHub Actions CI/CD
- App Store Review Guidelines
iOS Indie Developer & Creator
Full-time indie creator focusing on Apple ecosystem and AI integrations. Designed and released 4 major applications:
- Lumen Noise: Clock + ambient soundscapes (iOS, macOS, tvOS, visionOS)
- LeafAid: AI-powered plant caretaker and diagnostic assistant
- Flux IPTV: Universal playlist player with local latency checking
- Aibrary: Experimental app utilizing Sentry self-healing loops
Coupang (Seoul) · Senior iOS Engineer
Senior engineer at Coupang iOS Core Platform team, maintaining foundational frameworks for the largest e-commerce App in Korea. Led modularization and migrated core modules to native Swift. Operated fully in English and Korean.
ByteDance · iOS Engineer
Developed features for TikTok international e-commerce. Led optimization on Lynx dynamic page framework. Improved startup and load metrics by over 100% using container pools and pre-rendering. Formulated coding guidelines and worked on multi-platform Flutter/Android setups.
ShengHuo Info Tech · iOS Engineer
Shipped "DouBai Live" streaming e-commerce iOS app from scratch. Built video player flows, integrated HLS streaming, and handled WeChat Mini Program development.
Kumho Software (South Korea) · Frontend Engineer
Maintained internal enterprise portals. Worked with classic Web frameworks including ASP and .NET.
Nanjing Xiaozhuang & Woosong University · Software Engineering B.S.
Majored in Software Engineering. Selected as an exchange student to Woosong University in South Korea, completing bilingual coursework in system architectures and databases.
I am open for iOS/macOS custom development projects, performance optimization consulting, or general technical advising. Feel free to reach out.