Career

Working as a backend engineer in the Big Data Group, initially in the backend team, then moved to the xfunction team. Developing and maintaining systems using Golang, NextJS, ScyllaDB, k9s, ArgoCD, Kafka, and Spark for e-commerce platform infrastructure. Working in a Scrum development environment. Played a central role as a founding member of the xfunction team. Previously, communication between FE and BE teams and coordination with other departments was fragmented, resulting in significant delays — for example, a project scheduled for June release was delayed until October due to communication losses. For the new team, prioritized psychological safety by conducting Drucker-style exercises, fostering proactive communication among team members, and aligning expectations with PdM and stakeholders. As a result, eliminated unintended project delays to zero within 5 months of the team's establishment. Actively communicated with designers and across departments/teams, serving as a lead within the xfunction team.

Led development of an app and backend infrastructure for an Okinawa theme park business. Managed a team of 16 Vietnamese developers through English communication, including onsite collaboration in Vietnam (business trip and stay). Delivered IaC-based web infrastructure setup and release within 2 weeks of joining the project. Caught up with existing tech stack, configured DNS, built dev/stg environments, implemented release and monitoring to handle peak traffic of 1500 RPS. Implemented using PayloadCMS, SSTv3, and NextJS with REST API architecture. Designed a microservices-oriented architecture with service separation to distribute traffic spikes, with app backend handling 3000 RPS at origin. Built data analytics platform with Parquet format using Athena, Lambda, Glue, and Quick Suite (AWS), leveraging IaC and AI. Rapidly delivered native app development, backend construction, and admin panel implementation. Implemented an illustrated map feature that splits images and aligns them with coordinates. Faced tight deadlines and, as a tech lead, actively engaged with customers not only on technical aspects but also on business matters, providing proactive communication. When requirements expanded significantly beyond the initial scope, proposed AI integration to the customer as an alternative to team expansion, which became the company's first AI integration initiative using Devin. Reduced infrastructure costs by 30% through AWS serverless architecture, Savings Plans consultation with AWS, and Redis implementation to reduce RDS and Lambda cold start times. Built infrastructure as code (IaC) to create an AI-friendly environment from the start.

Developed a service that allows users to exchange points for stock rights as part of the Furusato Tax Donation system. Designed for high traffic, handling over 1000 RPS at peak access.

As a tech lead, I managed a team of three developers and three QAs. Proposed a system migration from one costing around 250,000 yen per month to a system costing around 10,000 yen per month using Lambda and CloudFront. Also improved and reduced the initially estimated monthly cost of 1.5 million yen from pre-sales by optimizing the system, including operational costs. To avoid dependency on specific individuals, introduced IaC and avoided manual migration tasks, writing everything in Golang. For the frontend, considering SEO and display speed, architected using Astro JS in an ISR-like configuration. Typically, team members are assigned single roles like FE engineer, BE engineer, and infrastructure engineer, but I was assigned to the project as a full-stack engineer because of my experience handling everything.

Worked on updating a corporate website. Collaborated with an overseas team and handled backend, frontend, and infrastructure as a full-stack engineer. Coordinated development with a team in Bangladesh, working asynchronously across time zones and holding meetings and specifications explanations as needed.

Developed the backend in Golang and communicated with the frontend via JSON-RPC. A fast-paced development environment. Led the implementation of Japan's first electronic application system for the 36 Agreement via e-Gov.

Responsible for adding new features, fixing bugs, providing APIs, and defining items using NoSQL. Also handled document creation and debugging environment setup.

Implemented scraping with BeautifulSoup4 in two weeks. Introduced parallel processing with Celery and ThredPoolExecutor, and distributed processing on 20 EC2 instances.

Added new features and created server-side logic.

Requirement definition, mock-up, DB design, PDF output feature implementation, rental server environment investigation, and deployment.

Automated back-office operations with NTT Advanced Technology's RPA software. Planned the framework for RPA creation and management.

Formatted Excel data into JSON and registered it in the REST-API using Django Rest Framework. Visualized data with plotly.js.

Loaded various data sources with Alteryx and integrated them into SQL Server. Implemented parallel processing, data anonymization, and batch processing.

Combined markup data with ASP.Net logic. Responsible for user interface, admin interface, and backend logic.

Aimed to import and sell raw ham from Spain, conducting supplier negotiations, farm visits, bacterial inspections, and customs clearance procedures. Acquired a food sanitation manager qualification. The project was suspended during fundraising.

Development of medical-grade polypropylene materials. Focused on suppressing injection molding distortion and developing materials to prevent contamination from UV exposure.

Explored PP-based separator film materials. Focused on heat resistance, puncture strength, and porosity.

Assisted in the research and development of polypropylene films at Sumitomo Chemical's petrochemical research institute. Supported the development of packaging materials and battery separators.