Kobayashi K

Senior Full Stack Developer

Medbury • Período integral

Apr 2023 - Present • 3 yrs 3 mos

● Hands-on designing and extending .NET and python/Django backend systems, tightening up checkout flows and improving API resilience across distributed services. ● Led the transition from a monolithic legacy e-commerce stack to a React frontend with Node.js microservices. We cut page load times by 35% and saw engagement climb by 22%. Also worked hands-on designing and extending .NET services, tightening up checkout flows and improving API resilience across distributed services. ● Architected and rolled out our AWS infrastructure (EC2, S3, RDS), right-sizing resources and cleaning up waste. Reduced infra spend by about 18% without sacrificing performance. ● Built and hardened REST APIs secured with JWT and OAuth2. Focused heavily on stability and observability — brought API uptime to 99.9%. ● Tuned PostgreSQL queries, added appropriate indexing, and introduced Redis caching for high-traffic endpoints. Average response times improved by about 40%. ● Set up CI/CD pipelines using GitHub Actions and Docker, moving us from manual releases to automated builds and deployments. Cut deployment time in half and reduced release friction significantly. ● Mentored five junior engineers through code reviews, pair sessions, and design walkthroughs. The team’s code quality and delivery velocity improved noticeably (around 40% by internal metrics). ● Worked closely with product, QA, and design to ship 20+ meaningful features over six months. Helped align technical decisions with business goals while keeping delivery predictable.

Full Stack Engineer

Consulting • Período integral

Jun 2020 - Feb 2023 • 2 yrs 8 mos

● Built and maintained Node.js and PHP backend services for healthcare platforms supporting 200K+ users, reducing recurring server-side errors by 20% through improved logging, validation, and exception handling. ● Developed reusable React and Angular components for patient-facing portals, improving usability scores by 30% and reducing support requests related to navigation and form errors. ● Designed and implemented RESTful APIs and modular microservices, improving service isolation and making new feature delivery faster and less risky. ● Introduced unit and API integration testing frameworks (Jest, PHPUnit, Postman collections), increasing automated test coverage and cutting post-deployment production issues by 25%. ● Managed and optimized MySQL and MongoDB databases, tuning indexes and query patterns to improve average query performance by 15% under peak load. ● Contributed actively in Agile/Scrum ceremonies, delivering 10+ high-priority features across multiple release cycles while maintaining sprint commitments. ● Developed frontend features with React, Angular, HTML5, CSS3, increasing user retention by 18%. ● Built backend services using PHP and Laravel, processing 500k+ transactions/month reliably. ● Assisted in unit and integration testing, decreasing post-release defects by 22%. ● Participated in code reviews and cross-team collaboration, enhancing team efficiency and knowledge sharing.