Sergey

Sergey Kovbasenko
Full Stack Developer (React • React Native • Node.js • TypeScript)

E-mail: [open contact info](look above in the "contact info" section)
LinkedIn: [open contact info](look above in the "contact info" section)
Telegram: @Sergey_Bayrak
Languages: English (Upper-Intermediate), Ukrainian (Native), Russian (Native)

Summary
Full Stack Developer with 4 years of experience building web and mobile applications.
Experienced with React, React Native, Next.js, Node.js, NestJS, and PostgreSQL.
I enjoy solving technical problems, building reliable applications, and writing clean, maintainable code. I have experience working on both frontend and backend, reviewing code, and helping teammates.

Key skills
• Full-stack application development
• Frontend architecture (React, React Native)
• Backend API development
• Performance optimization
• Code reviews and mentoring
• Testing (unit, integration, end-to-end)
• Agile team collaboration

Technologies
• Languages: JavaScript, TypeScript
• Front-End: React, React Native, Next.js, Redux, HTML, CSS, SASS/SCSS, Tailwind, Styled Components
• Back-End: Node.js, Express, Nest.js
• Networking: REST, Websocket, GraphQL
• Databases: PostgreSQL, TypeORM, Sequelize
• Cloud & DevOps: AWS (S3), Vercel, Heroku, Git, Docker
• Workflow: Agile, Kanban, Jira

Professional Experience
Middle Full Stack Developer
SysGears, Dnipro, Ukraine
May 2022 – Aug 2024
• Built web and mobile applications using React, React Native, Next.js, NestJS, and PostgreSQL.
• Implemented new frontend and backend features across multiple services.
• Developed and maintained microservices.
• Reviewed pull requests and mentored junior developers.
• Optimized application performance and resolved production issues.
• Collaborated with designers, QA engineers, and product managers in Agile teams.

Full Stack Developer
Meg Analytics, London, United Kingdom
Oct 2020 – May 2022
• Developed frontend and backend features.
• Built REST APIs.
• Fixed bugs and improved existing functionality.
• Worked with React, Redux, Express, and PostgreSQL.
• Participated in code reviews and team discussions.

Key Projects
Psychological Support Service
Full Stack Developer
Stack: React Native, Next.js, Nest.js

Jan 2023 – Aug 2024
• Developed a web and mobile platform for anonymous psychological support.
• Implemented frontend and backend features across multiple services.
• Worked within a microservices architecture.
• Improved application stability through bug fixing and performance optimization.

Fleet Management System
Full Stack Developer
Stack: React, React Native, Nest.js

May 2022 – Jan 2023
• Developed web and mobile applications for fleet and vehicle management.
• Implemented vehicle rental workflows.
• Built dashboards displaying fleet statistics and operational metrics.
• Contributed to both frontend and backend development.

Alias Mobile Game
Solo Developer
Stack: React Native

Oct 2021 – May 2022
• Built a cross-platform mobile implementation of the Alias party game.
• Developed custom animations and gesture-based interactions.
• Optimized rendering performance and fixed UI issues.

Financial Analytics Platform
Full Stack Developer
Stack: React, Redux, Express

Oct 2019 – May 2022
• Developed dashboards for portfolio and market analytics.
• Implemented position tracking and risk analysis features.
• Built reusable React components and integrated REST APIs.

Documentation Streamlining Platform
Front End Developer
Stack: React, Redux

Oct 2019 – May 2022
• Developed document management functionality.
• Implemented document annotation features.
• Improved navigation and rendering for PDF and DOC documents.

Education
Technologies of Medical Diagnostics and Treatment, Laboratory Diagnostics
Taras Shevchenko National University of Kyiv, Ukraine
Bachelor degree