Senior Full-Stack Engineer

Results-driven Senior Full-Stack Engineer with 12+ years of experience delivering scalable solutions across diverse industries. Specialized in backend development (C#/.NET, Python, Ruby) with proven track record of optimizing system performance, leading technical teams, and implementing DevOps best practices. Passionate about clean code architecture, AI-driven development (Vibe Coding), and developer experience (DevEx).

Work Experience

Backend Lead / Full-Stack Developer

Frontier.cool (Taipei, Taiwan) Oct 2024 – Present

Led a team of 4 backend developers, responsible for core backend and DevOps operations. Refactored a large legacy codebase, optimized API performance, and improved test coverage and code quality.

  • Led backend team and implemented CI/CD pipelines.
  • Refactored 18,000-line god class into 10 modular classes.
  • Reduced critical API response time from 5 seconds to 200 ms.
  • Cut deployment time by 83% through full automation.

Senior Ruby Developer / Technical Lead

Rakuten (Osaka, Japan) Apr 2022 – Feb 2024

Maintained a mature Ruby project as the sole developer, handling DevOps, performance tuning, and feature refactors. Later, as a Technical Lead, I led a team of 5 developers, re-architected a monolithic repository, and mentored teammates.

  • Speaker at Rakuten Tech Conference 2022.
  • Re-architected a monolithic repository into 5 domain-specific modules.
  • Reduced 8000+ test runtime from 70 minutes to 8 minutes.

Ruby on Rails Developer and Web team leader

Racbit (Taipei, Taiwan) 2015.12 - 2017.4

Led a team of two Ruby on Rails developers and one product manager to build a sports event SaaS platform.

  • Developed hundreds of features in an agile environment.
  • Mentored junior developers through code reviews and pair programming.
  • Improved email sending efficiency by 8x using AWS SDK and multi-threading.

Skills

PROFICIENT

C#, .NET, Python, Ruby, Rails, ASP.NET, SQL, Git, CI/CD, AWS, Unit Testing, Agile

KNOWLEDGABLE

REST APIs, OAuth, ISO 27001, STRIDE Threat Modeling, Monitoring, JavaScript, JQuery, HTML/CSS

USED PREVIOUSLY

Java, Docker, MS-SQL, Android, PHP, WordPress

Projects

Smells to Refactoring Guide

Author

Ongoing

https://smells-to-refactorings.gitbook.io/smells

A curated guide on code smells and refactoring techniques. This guide helps developers identify common issues in their code and provides clear, actionable steps to improve it.