Tokyo, Japan | kaz.redhot1201@gmail.com | GitHub
Full Stack Engineer and Tech Lead with over 5 years of experience driving the development of complex platforms and modern web applications. Proven track record of accelerating team productivity, establishing robust technical architectures, and contributing to the maximization of team output. I specialize in bridging the gap between technical implementation and business requirements, consistently delivering systems that solve real-world problems and enhance Developer Experience (DX).
Backend Engineer (Tech Lead) — New Development of Reconciliation Service | March 2026 - Present Technologies: Go (REST), Kafka, CircleCI, AWS
- [Architecture & Product Strategy] Driving the core architectural and schema design for a generic reconciliation service. The service is designed to eliminate product-specific data silos and prevent users from duplicating reconciliation work across multiple accounting services.
- [Cross-Border Leadership] Bridging the gap between Japan-based Product Owners/Architects and a Vietnam-based engineering/QA team. Focused on detailed spec analysis, core architectural alignment, and core implementation, while partially delegating development to the Vietnam team and ensuring quality through comprehensive PR reviews.
Full Stack Engineer (Sub-Manager) — New Development of Accounting Peripheral Systems | November 2024 - Present Technologies: React, TypeScript, React Router V7, Go (gRPC), Kafka, CircleCI, AWS
- [Complex Feature Delivery] Spearheaded the end-to-end design, implementation, and testing of technically challenging core features, including user onboarding and subscription management functionalities.
- [AI-Driven Architecture] Established robust coding and architectural standards for both frontend and backend that serve as critical guardrails for Agentic Coding. This ensured that despite heavy AI utilization by the team, the codebase remains highly homogeneous and maintainable.
- [Team Empowerment] Facilitated entirely English-based development for a mixed-nationality team. Successfully transitioned 2 Japanese members to English-first development—mentoring them on discussing and thinking in English—without any drop in project velocity.
Full Stack Engineer — Revamp of Accounting Management System | July 2024 - October 2024 Technologies: React, TypeScript, JavaScript, Ruby on Rails, CircleCI, AWS
- [Sales Strategy Enablement] Flawlessly released a third-party API integration to fetch corporate data for tenant attribute analysis. Combined with a new auto-fill feature, this significantly enriched tenant profiles and empowered the sales team to execute highly targeted campaigns.
- [Stakeholder Alignment] Spearheaded the adoption of Scrum, establishing bi-weekly iterative feedback loops with Product Owners and Customer Support, which significantly increased stakeholder satisfaction and delivered the required features on time.
Frontend Lead — New Development & Operation of Inventory Management System | February 2023 - June 2024 Technologies: React, TypeScript, Next.js (Pages Router), Vite, Material UI, TanStack Query, GCP
- [Business Impact] Led the end-to-end development of a new inventory management system from scratch to release in just 6 months. The system successfully replaced legacy manual processes, saving an estimated 10-15 hours per week per staff member.
- [Developer Experience] Eliminated UI regressions entirely by incorporating Visual Regression Testing (VRT), strict linters, and formatters into the CI/CD pipeline.
- [Productivity Multiplier] Designed file generation templates (combining Atomic Design and Screaming Architecture) and comprehensive coding guidelines. This reduced the time required to review PRs from newly joined interns to just 5-10 minutes each.
Frontend Engineer — Frontend Cross-Functional Organization | November 2022 - June 2024 Technologies: React, TypeScript, Next.js, Material UI
- [Mentorship & Onboarding] Planned and created a comprehensive React/Next.js onboarding curriculum for prospective interns. Successfully onboarded 5+ developers, enabling individuals with zero prior React experience to commit code to production within their first week.
Full Stack Engineer (Sub-Manager) — Professional Appraisal Management System | October 2022 - February 2023 Technologies: React, TypeScript, Next.js, Go, Hasura, GCP (Cloud Run, Cloud SQL)
- [Debt Reduction] Inherited an unreleased, heavily indebted project from another team. Established clear coding rules and led parallel refactoring efforts, improving development speed and allowing new members to smoothly onboard. Instilled a culture of writing Architecture Decision Records (ADRs).
Development Camp Working Group Leader | June 2022 - February 2023
- Led the planning and execution of the company's first-ever internal development camp, managing budget, schedule, and stakeholder alignment. Achieved high satisfaction, with 89% of participants expressing a desire to return for the next iteration.
Full Stack Engineer — Store Purchase & Product Master Management Systems | July 2021 - October 2022 Technologies: React, TypeScript, Next.js, Go, Hasura, GCP
- Played a key role in the frontend and backend design of multiple internal management systems. Handled UI/UX implementation, API design, and the introduction of comprehensive monitoring/alerting (Datadog, Sentry), ensuring high system reliability.
Previous experience includes full-time, part-time, and internship software engineering roles at BuySell Technologies and Link Edge Inc. maintaining core applications (2019-2021).
Driven by technical curiosity and a desire to interact with global engineering communities.
- Valibot: Bug fixes (e.g., email method) and documentation expansion.
- TypeScript ESLint: Addressed bugs and expanded tests for Good First Issues.
- Scrum Fest Kanazawa 2025: Building Common Understanding with "Concrete Artifacts": Optimization of Communication in Dev Teams
- Frontend Study Session (GENDA x ZEST x BuySell): Post Zod - Introduction to Valibot
- Languages: TypeScript, JavaScript, Go, Python, Ruby, GraphQL, SQL, HTML/CSS
- Frameworks: React, Next.js, Vue, Ruby on Rails
- Cloud & DevOps: AWS, GCP, Terraform, Docker, CircleCI, GitHub Actions
- Tools: PostgreSQL, Kafka, Datadog, Sentry
- Certifications: Google Cloud Professional Cloud Architect (Certificate)
- Spoken Languages: Japanese (Native), English (Business, TOEIC 855)
- University of the People: B.S. in Computer Science (Jun 2024 - Jun 2026)
- Sophia University: B.A. in International Relations (Apr 2016 - Mar 2021)
- Tochigi Prefectural Ishibashi High School: Graduated Mar 2016