About Me
About Me
10+
Years Experience
8+
Projects
4+
Languages
With C#/.NET, Java, and TypeScript (Next.js) as my core stack, I've spent about 10 years in system development. I thrive on going beyond my assigned scope to maximize the team's overall output.
Full-Stack Development
From requirements and design to frontend/backend implementation and AWS infrastructure. I've led challenging projects to release as a PL.
AI-Driven Development
Actively leveraging LLMs to boost development efficiency, proposing innovative solutions and new technology adoption.
Team Building
Pair programming, code reviews, and strength-based task allocation — creating an environment where everyone can perform at their best.
What I Deliver
Hit the Ground Running
Proficient in multiple stacks — C#, Java, TypeScript. Quick to ramp up on existing codebases and deliver from day one.
End-to-End Ownership
From requirements and design to implementation and infrastructure — I handle the full lifecycle. Minimal direction needed.
Project Turnaround
Quickly identify code quality and design issues, then execute fixes. Proven track record of rescuing delayed and leaderless projects.
Technology & Innovation
AI-driven development with LLMs, modern tech adoption — I actively propose solutions that boost development efficiency.
Skills
Skills & Expertise
Languages
4Frameworks
6Databases
5Infrastructure
11Business Domains
4Career
Career History
Cloud Accounting Service for Enterprises
April 2024 – Present|1 year 10 months
Role
Tech Stack
Details
- Full-scratch development of a cloud accounting service using microservices architecture
- Cross-functional contribution across FE/BE/infrastructure as a contract engineer
- Currently responsible for closing, fixed assets, journal/balance import processing, and external accounting tool integrations
- Designed and implemented backend foundations: external communications, middleware, DB access layer, and xUnit core utilities
- Architected project structure following Clean Architecture with dependency inversion
- Built CI/CD pipeline using AWS CodePipeline
- Automated DB backup using Lambda + Step Functions
Achievements
- ▶Early delivery of BE foundations (external comms, middleware, DB access, test infrastructure) to streamline team development
- ▶Expanded coverage across FE/BE/infrastructure, eliminating team bottlenecks
All-in-One ERP Package for Apparel Industry
November 2023 – March 2024|5 months
Role
Tech Stack
Details
- Customization development of an all-in-one ERP system for apparel (sales, inventory, procurement management)
- Focused on inter-store inventory adjustment feature, from detailed design through unit testing
- Created Factory Pattern for CSV/JSON Export/Import processing, standardizing workflow, validation, and output logic
Achievements
- ▶Developed a reusable Export/Import Factory and deployed it across the team, significantly improving development efficiency
- ▶Completed assigned tasks ahead of schedule, enabling additional support for other team members
E-Commerce Management System (Full Scratch)
April 2021 – November 2023|2 years 8 months
Role
Tech Stack
Details
- Full-scratch development of a package covering order, inventory, customer, shipping, and billing management
- Dual architecture: Web app (Java — master, inventory, shipping) and Desktop app (C# — orders, customers, billing)
- Designed API integrations with Amazon, Rakuten, and Yahoo for automated order/customer data import
- Led system design (screen/API design) for inventory management, EC integrations, and master data features
- End-to-end ownership for custom features: requirements, acceptance testing, client training, and maintenance
- Design lead for standard package; project leader for multiple client-specific customization deliveries
Achievements
- ▶Recovered manufacturing delays by handling both design and implementation in parallel during waterfall development
- ▶Covered all phases from requirements to maintenance, driving overall project delivery
Ticket Consignment Billing & Settlement System
July 2020 – March 2021|9 months
Role
Tech Stack
Details
- Development of a billing and settlement management system for ticket sales companies
- Designed and implemented core journal entry generation logic from transaction data
- Optimized numerous batch processes through execution-plan-aware query design
Achievements
- ▶Accurately implemented complex journal entry logic, delivering a high-quality system
- ▶Optimized batch processing performance through execution-plan-based SQL tuning
Bond Record Management System Replacement
March 2019 – June 2020|1 year 4 months
Role
Tech Stack
Details
- Replacement development of a bond record management system
- Took over full project management after PL departure: progress tracking, client negotiations, and team coordination
- Designed and implemented VBA-based report generation tool
Achievements
- ▶After PL departure, took over project management (progress, client relations, team management) and delivered to release
- ▶Reduced batch processing time from 1 hour to 15 minutes through proper index design and SQL tuning
Trust Bank Bond Trading System Replacement
July 2016 – February 2019|2 years 8 months
Role
Tech Stack
Details
- Replacement of a bond trading system for one of Japan's only 3 asset management trust banks
- Promoted from spot testing role to settlement team leader by proactively absorbing domain knowledge
- Owned core logic for settlement, reports, repo trading (collateral, mark-to-market, margin call calculations)
- Managed a 10-member settlement team: progress tracking and task assignment
- COBOL core functions executed via JP1 job scheduling (equivalent to AWS Step Functions/Lambda)
Achievements
- ▶Earned client trust by mastering core function specifications beyond anyone else, leading to team leader promotion
- ▶Led 10-member settlement team to successful delivery of all assigned releases
Major Bank Core System Maintenance
July 2015 – June 2017|2 years
Role
Tech Stack
Details
- Maintained and enhanced branch terminals, ATMs, and web services; supported system integration with another bank
- Delivered quality-first implementation and testing for mission-critical systems with zero tolerance for defects
Achievements
- ▶Completed development under strict zero-defect quality standards, building a strong foundation for quality-conscious engineering
Pension System Modification (Year 2025 Japanese Calendar Issue)
May 2014 – June 2015|1 year 2 months
Role
Tech Stack
Details
- Modified internal date handling to expand Japanese era year fields from 2-digit to 3-digit format (Showa 100 year problem)
- Developed and tested date processing logic modifications in COBOL
Achievements
- ▶Gained foundational development skills by contributing to a large-scale pension system in first year of career
Personal Works
Personal Projects
SaaS Resitoly
AI-powered expense management SaaS that auto-analyzes receipts via OCR + LLM
Blog
Blog
Coming Soon — Technical articles in progress
Contact
Contact
Feel free to reach out. I'm open to project consultations and work opportunities.
Send an Email
s_nakagawa@taluslab.com