Bater Chen

Delivering real user value with AI, crafted through tidy, maintainable code.

📍 Taipei, Taiwan
📧 baterme[at]gmail.com
🔗 LinkedIn
📝 Blog
📝 Smells to Refactoring

🧠 Summary

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).

🛠️ Skills

  • Backend: C#/.NET, Python, Ruby, ASP.NET, Rails
  • Fronted: Vue.js, Angular.js
  • DevOps & Infrastructure: CI/CD, AWS (Lambda, EC2, Route 53), Git, Monitoring
  • Database & API: SQL, REST APIs, OAuth 1/2
  • Quality & Process: Unit Testing, ISO 27001, Agile, STRIDE Threat Modeling

💼 Experience

Frontier.cool (Taipei, Taiwan)

Backend Lead / Full-Stack Developer
Oct 2024 – Present

  • Led a team of 4 backend developers (2 senior, 2 mid-level), responsible for core backend and DevOps operations.
  • Led backend team and implemented CI/CD pipelines to streamline release operations
  • Refactored 18,000-line god class into 10 modular classes based on functional domains
  • Optimized critical API performance, reducing response time from 5 seconds to 200 ms
  • Increased unit test coverage from <10 to 500+; enforced pre-release threat modeling (STRIDE)
  • Reduced code warnings and improved code quality by 8.6% across releases
  • Cut deployment time by 83% through full automation
  • Boosted team collaboration with +4 hours/month of structured dev sync
  • Maintained ISO 27001-aligned security practices and system observability
  • Managed AWS infrastructure: Lambda, EC2, Route 53

PM
May 2024 – Oct 2024

  • Coordinated cross-functional teams (FE, BE, QA, UI/UX, PO) to deliver feature roadmap on time, resolving spec ambiguities and release blockers under tight timelines.
  • Initiated Git i18n tooling with proper version control, reducing PM maintenance cost and time, and avoid accidental regression to previous text.
  • Managed the timely release of FabriSelect v2.0, enabling clients to quickly demo fabrics at exhibitions
  • Served cross-role responsibilities as Project Manager

Frontend Developer / Lead
Mar 2024 – May 2024

  • Team size: 2 senior frontend develops
  • Implemented QR code labeling feature, adopted by clients for streamlined material management
  • Integrated online spreadsheet functionality, enabling users to perform bulk editing and improving data management efficiency
  • Developed 3D material viewer, enabling online preview of 2D scanned images as 3D objects, enhancing client visualization and decision-making
  • Led frontend E2E testing with CI/CD pipelines

Rakuten (Osaka, Japan)

Senior Ruby Developer
Apr 2022 – Feb 2024

  • Maintained mature Ruby project as sole developer
  • Handled DevOps, performance tuning, and feature refactors
  • Speaker, Rakuten Tech Conference 2022

Technical Lead
Jul 2020 – Mar 2022

  • Team size: 5 ruby develops
  • Led the end-to-end development of a new communication system for internal and external users (web UI and email).
  • Designed system architecture and addressed technical debt to improve code quality.
  • Mentored teammates, coached skill development, and removed team blockers to maximize output.
  • Re-architected a monolithic repository into 5 domain-specific modules for better segregation.

Rails Developer
Jul 2018 – Jun 2020

  • Maintained an 8-year-old internal system managing global merchants.
  • Reduced 8000+ test runtime from 70 minutes to 8 minutes through parallel execution and API mocking.
  • Increased test line ratio from 110% to 160%.
  • Introduced automated JavaScript and frontend testing into the legacy stack.
  • Upgraded Ruby and Rails from End-of-Life to the latest versions, applying clean code principles during refactoring.

InfoCentric (Melbourne, Australia)

Ruby on Rails Developer
Jul 2017 – Nov 2017

  • Integrated Garmin and Fitbit APIs using OAuth 1 and 2 for a health device platform calculating insurance discounts.
  • Achieved a 110% code-to-test ratio for all features and models.
  • Authored deployment documentation and developed an API for QA to generate test data.

Racbit (Taipei, Taiwan)

Ruby Developer / Web Team Lead
Dec 2015 – Apr 2017

  • Led a team of two Ruby on Rails developers and one product manager to build a sports event SaaS platform (official website, cashflow, ticket selling, online shop).
  • Developed hundreds of features in an agile environment.
  • Planned and facilitated daily scrums, weekly estimations, and retrospectives.
  • Prepared technical design and release documentation.
  • Mentored junior developers through code reviews, pair programming, and weekly meetings.
  • Managed AWS services (EC2, S3, RDS, Mailgun) for application hosting.
  • Improved email sending efficiency by 8x using AWS SDK and multi-threading, sending 100 emails with business logic in 60 seconds.

Hyweb Technology Co. (Taiwan)

Java Engineer
Sep 2012 – May 2015

  • Built foreign labor auditing system for the Taiwanese government, used daily by hundreds of employees.
  • Improved worker efficiency by reducing paper workflows, saving each employee 5 hours per day.
  • Designed, implemented, deployed, and maintained web applications.
  • Resolved customer issues, conducted product research, and developed solutions from feature requirements.
  • Maintained a coding rule wiki to ensure knowledge reusability and accessibility.

1111 Job Bank (Taiwan)

Information Architecture
Aug 2009 – Sep 2011

  • Led website operations and UX design, including wireframe creation and UX report generation.
  • Managed marketing events, official social media (Facebook, Plurk), and EDM systems.
  • Recruited web designers and .NET programmers.
  • Promoted from Assistant to Manager within 2 years.

🎓 Education

  • National Chung Cheng University, Taiwan — B.S.
    2004 – 2008
  • Institute for Information Industry, Taiwan — Software Dev Program
    Feb 2012 – Aug 2012

🌐 Languages

  • Mandarin: Native
  • English: Fluent (TOEIC > 700)