Charles Chiang — Senior iOS Engineer
Senior iOS & macOS Engineer

Tien Chang
Chiang

Crafting secure, scalable mobile experiences

7+ years building production-grade iOS applications — from security-first health platforms to high-performance networking layers. Based in Taiwan, open to Europe & New Zealand.

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7+
Years iOS
Engineering
100k+
Active Users
Served
<0.1%
Crash Rate
in Production
CharlesApp.swift
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Charles Chiang
Tien Chang Chiang
7+
Years of iOS
Experience
7
Companies
Across 3 Countries
100k+
Active Users
in Production
<0.1%
Crash Rate
Maintained
About

Engineering with
precision & care

I am a Senior iOS & macOS Engineer with over 7 years of experience building applications that people depend on every day. I specialise in SwiftUI, MVVM-C and Swift Package Manager, with a deep focus on security, performance, and code quality.

"Four walls keep you focused, but the world gives you inspiration."

My background spans security-first health platforms, real-time networking layers, and large-scale codebase migrations. I build CI/CD pipelines that sustain sub-0.1% crash rates in production, and I actively use AI-assisted tools — Cursor, Antigravity, Claude Code — to ship faster without cutting corners.

I am currently based in Kaohsiung, Taiwan, and open to relocating to Europe or New Zealand, or contributing remotely immediately with zero notice period.

iOS / macOS
Swift SwiftUI UIKit RxSwift Combine Objective-C
Architecture
MVVM-C SPM TDD CocoaPods BFF Pattern
CI/CD & Tooling
Fastlane GitHub Actions Bitrise Xcode Jira
Security
Privacy Encryption TLS Pinning Biometric Auth
AI Tooling
Cursor Antigravity (Google AI IDE) Claude Code
Languages
Mandarin — Native English — C1 Japanese — A2 German — A1 (learning)
Experience

Work History

Dec 2021 — Present Tokyo, Japan · Remote
Genesis Healthcare Co., Ltd.
iOS Developer
  • Security & Authentication: Handled highly sensitive medical records. Ensured robust encryption for data storage, secure network transmission, and strict user authentication flows to prevent unauthorized access.
  • Automation & Test Quality: Established strict TDD workflows and automated CI/CD pipelines (Fastlane/GitHub Actions). Integrated iOS-side telemetry to proactively monitor performance and ensure <0.1% crash rates across 100k+ active users.
  • Feature Ownership: Worked closely with cross-functional teams (security, backend, PMs, designers) to deliver scalable features end-to-end using SwiftUI and MVVM-C + SPM modularisation across 3 time zones.
Oct 2021 — Apr 2023 Maryland, USA · Remote
Teon LLC.
iOS & macOS Developer — Contract
  • Network Resilience & Real-Time Data: Engineered a high-performance networking layer using custom VPN protocols and persistent sockets. Successfully managed massive binary data streams in the background, ensuring absolute data integrity, stable connectivity, and crash-free UI updates.
  • Background Execution & Battery Life: Optimized complex background processes to minimise battery drain and CPU usage, ensuring the app remains lightweight and responsive.
  • Data Integrity: Implemented custom error correction logic to ensure 100% data delivery reliability, similar to sensor data synchronisation requirements.
Jan 2021 — Jun 2021 Taipei, Taiwan
ICSGAME Co., Ltd.
iOS & Front-End Engineer
  • Launched the iOS version of the product from scratch using Swift, ensuring feature parity with the web platform and aligning with strategic business goals.
  • Developed and optimised the web frontend using Vue.js, leveraging cross-domain knowledge to bridge the gap between mobile and web experiences.
  • Implemented a PWA solution, extending product reach and improving accessibility for mobile web users.
Feb 2020 — Aug 2020 Kaohsiung, Taiwan
Hamastar Technology Co., Ltd.
Front-End Engineer
  • Maintained and optimised large-scale remote learning platforms using Angular, ensuring high availability during peak traffic periods.
  • Managed the architecture of multiple regional sub-sites, improving code maintainability and scalability for educational institutions.
Dec 2018 — Jul 2019 Kaohsiung, Taiwan
HyperLight Digital Media Marketing Co., Ltd.
iOS Engineer
  • Migration: Led the strategic refactoring of a legacy Objective-C codebase into modern Swift. Successfully modernised the app architecture while maintaining 100% backward compatibility and interoperability between both languages. Defined modular architecture guidelines to improve team velocity and code maintainability.
  • Legacy Code Maintenance: Stabilised core features by introducing strict typing and modularisation, significantly reducing technical debt and enabling faster feature iteration.
  • Mentorship & Code Quality: Led asynchronous technical discussions across remote teams. Enforced high code quality by conducting rigorous PR reviews, mentoring developers, and maintaining comprehensive technical documentation.
Dec 2017 — Jul 2018 Kaohsiung, Taiwan
Kidtech Co., Ltd.
iOS Engineer
  • Collaborated closely with backend teams to integrate complex Java Spring APIs, enhancing data synchronisation and system reliability.
  • Developed and maintained utility and public welfare apps, focusing on delivering a smooth and intuitive user experience.
Feb 2016 — Nov 2017 Kaohsiung, Taiwan
Mycena Co., Ltd.
iOS Engineer
  • Developed a comprehensive guide assignment system for travel agencies using Swift, digitising workflows and increasing operational efficiency.
  • Built customised property management applications, supporting B2B clients in streamlining their daily business operations.
Work

Selected
Projects

GeneLife 3.0
App Store ↗

DNA-based personalized health and wellness companion for Genesis Healthcare — Japan's #1 DTC genetics brand with 2.7M+ analyses conducted. Designed security-first data flows with encrypted storage, TLS-pinned transmission, and biometric authentication. Built Fastlane + GitHub Actions CI/CD pipelines and led SwiftUI migration using MVVM-C + SPM modularisation across a cross-functional team spanning 3 time zones.

SwiftUI MVVM-C SPM HealthKit Fastlane Security
100k+ active users · <0.1% crash rate
nthLink
App Store ↗

Free censorship-circumvention VPN used by journalists and human rights activists in restricted regions worldwide. Engineered a custom VPN + persistent-socket networking layer handling large binary streams in the background with crash-free UI under peak load. Implemented FEC (forward error correction) logic guaranteeing 100% data delivery reliability, and profiled background tasks to measurably reduce CPU wake-ups and battery drain.

Swift NetworkExtension Combine VPN macOS FEC
Available globally · no registration required
Beyond the Code

Digital Nomad &
Life on the Road

I've been working remotely for companies in Japan and the US while living and traveling through 25 countries. My months in Europe weren't a vacation, it was a real-world challenge. I wanted to prove that I could build great software from anywhere, work with different cultures, and always ship on time.

Finland
Germany
Switzerland
Slovenia
Asia & Pacific
🇹🇭Thailand
🇯🇵Japan
🇵🇭Philippines
🇲🇴Macau
🇭🇰Hong Kong
🇨🇳China
Americas
🇺🇸United States
Europe 18 countries
🇬🇧United Kingdom
🇫🇷France
🇩🇪Germany
🇨🇭Switzerland
🇳🇱Netherlands
🇧🇪Belgium
🇱🇺Luxembourg
🇦🇹Austria
🇱🇮Liechtenstein
🇩🇰Denmark
🇸🇪Sweden
🇫🇮Finland
🇮🇹Italy
🇨🇿Czech Republic
🇭🇺Hungary
🇸🇰Slovakia
🇭🇷Croatia
🇸🇮Slovenia
25
Countries
18
European Nations
3
Continents
0
Missed deadlines
while traveling
Contact

Let's work
together

Open to great opportunities in Europe and New Zealand

Whether you're building a health-tech platform, a consumer app at scale, or anything that demands high reliability — I'd love to hear about it. I'm available immediately with zero notice period.

charlesjiang127@gmail.com
linkedin.com/in/charles50g
github.com/CharlesChiang
Available Now
Zero notice period.
Ready to start immediately.

Based in Kaohsiung, Taiwan. Fully prepared to relocate or begin remotely. Experienced working across multiple time zones with distributed teams in Tokyo, Maryland, and Taipei.

🇩🇪 Germany 🇪🇺 Europe 🇳🇿 New Zealand 🌐 Remote