- 👋 Hi, I’m Hitoshi Yamaguchi
- 👀 I’m interested in ... system engineering(Ruby AWS GCP Azure),
- Resume ... https://docs.google.com/spreadsheets/d/1WfGcuWQSwezLkiv0Gb1-onehJR6NenR2PCcVDS1AUs8/edit#gid=1218823470
- Lapras ... https://lapras.com/public/J7KTMYZ
As a Web engineer with about six years of experience, I have been engaged mainly in development using Ruby on Rails. With a strong interest in handling high-traffic and real-time processing, I have worked across both frontend and backend, covering all phases from basic design to maintenance and operations.
My experience includes developing APIs for matching and rental-space reservation systems, building data pipelines, and creating GeoJSON data for parcel history and registration records for eMAFF (Ministry of Agriculture, Forestry and Fisheries).
Most recently, I have been involved in the development and maintenance of a FAQ/Helpdesk product, contributing to a wide range of areas such as new feature development, existing feature enhancement, AI integration, cloud migration, and operational improvements.
In particular, I designed and implemented GPT response features using Azure OpenAI Service, including prompt management, log design, and model EOL handling (tenant migration), establishing a stable operational framework for AI functionality. I also supported the migration from an LXC environment to AWS, handling authentication setup, log monitoring, timezone adjustments, and cron job alignment to ensure a smooth transition with minimal operational impact.
On the security side, I conducted impact analysis, compatibility testing, and QA verification during updates of authentication and XML-related libraries (ruby-saml, nokogiri), successfully completing EOL and vulnerability mitigations. I also reviewed and tested FAQ search and Solr re-indexing processes, as well as fuzzy search functionality, helping maintain search stability and response quality.
Beyond development, I took responsibility for post-release quality assurance, including PR reviews, acceptance testing, and performance monitoring using CloudWatch, bullet, and profiler to detect N+1 issues and measure performance. I have also worked actively on documentation and specification materials to reduce dependence on individuals and promote knowledge sharing within the team.
For over two years, I have maintained a 100% engagement rate, consistently contributing across development, maintenance, AI integration, cloud operations, review, and QA. Going forward, I aim to leverage these experiences to design and maintain high-quality, long-term stable web services that integrate search technology, AI, and cloud infrastructure.