Serhii

SERHII DANCHUK
REACT FRONTEND DEVELOPER | JAVASCRIPT | NEXT.JS
Ukraine · Remote only | [open contact info](look above in the "contact info" section) | [open contact info](look above in the "contact info" section)
[open contact info](look above in the "contact info" section) | Telegram: @serhii_danchuk
PROFESSIONAL SUMMARY
React Frontend Developer with 6+ years of commercial experience building, optimizing, and maintaining production web applications. Skilled in React, JavaScript, Next.js, and modern frontend architecture, with experience delivering projects from scratch, developing reusable components, and integrating REST APIs. Improved frontend performance by 25% through legacy code refactoring and achieved Google PageSpeed Insights scores of up to 100/100 through loading, asset, and code optimization. Previously promoted to Frontend Team Lead.
SKILLS
Frontend: React, JavaScript (ES6+), TypeScript, Next.js, HTML5, CSS3
State Management & APIs: Redux Toolkit, TanStack Query, REST APIs
Testing: Vitest, React Testing Library
Development Tools: Git, Webpack, Node.js
Additional Expertise: Responsive Web Development, Performance Optimization, Chrome Extensions, UI/UX Implementation, Chart.js
PROFESSIONAL EXPERIENCE
Frontend Developer | InsulaLabs
Jan 2025 – Present | Remote, Ukraine
• Develop and maintain React applications across multiple production projects, delivering features within existing frontend architectures.
• Build responsive, pixel-accurate interfaces from UI/UX designs for desktop, tablet, and mobile.
• Create reusable UI components, interactive forms, and visual effects; investigate and resolve frontend issues.
• Collaborate across codebases to improve application stability, maintainability, and performance.
Team Lead Frontend Developer | Admiral Studios
Jul 2024 – Jan 2025 | Remote, Ukraine
• Progressed from Frontend Developer to a frontend team leadership role.
• Supported frontend delivery and development across ongoing projects.
Frontend Developer | Admiral Studios
Feb 2023 – Jul 2024 | Remote, Ukraine
• Developed a React-based plugin from scratch and implemented its frontend functionality.
• Built image-editing features for a photo editor and contributed features and fixes to React and Next.js applications.
• Created data visualizations with Chart.js; maintained two WordPress websites and delivered ongoing improvements.
Frontend Developer | Relokia
Sep 2021 – Feb 2023 | Ternopil, Ukraine
• Developed and maintained production frontend features, including UI/UX improvements and a standalone React Chrome Extension.
• Replaced legacy jQuery with vanilla JavaScript, reducing code complexity by 30% and improving frontend performance by 25%.
• Improved Lighthouse/PageSpeed results with lazy loading, media optimization, code refactoring, and Webpack configuration.
• Built custom Zendesk Help Center themes and WordPress themes, templates, and features using JavaScript, HTML, CSS, and PHP.
Frontend Developer | Wise Solutions
Jul 2020 – Sep 2021 | Ternopil, Ukraine
• Built responsive landing pages and web interfaces using JavaScript, HTML5, CSS3, and jQuery; integrated UI into PHP-based applications.
• Optimized frontend loading and achieved Lighthouse/PageSpeed scores close to 100 on relevant projects.
EDUCATION
Master’s Degree, Software Engineering | Khmelnytskyi National University | 2016–2022
LANGUAGES
English — B1–B2