Hennadii

HENNADII BIRCHENKO
Front-End Developer (React / TypeScript)
Cherkasy, Ukraine | [open contact info](look above in the "contact info" section) | [open contact info](look above in the "contact info" section) | LinkedIn: [open contact info](look above in the "contact info" section)

PROFILE
Front-end developer with 4+ years of hands-on commercial experience building production React applications. Comfortable with
React fundamentals — components, hooks-based state management, controlled forms, list rendering, and component
composition. Experienced integrating REST APIs, including async data fetching, loading states, and error handling. Solid HTML,
CSS, and modern JavaScript (ES6+); working knowledge of TypeScript and continuing to deepen it on the job. Used to working
inside existing codebases, following established conventions, and collaborating through Git/GitHub branches, commits, and pull
requests.

KEY SKILLS
Core: React, JavaScript (ES6+), HTML5, CSS3, TypeScript, React Router, Next.js
State & Data: Redux, Redux-Saga, Zustand, REST API integration, GraphQL, Swagger
Styling: Tailwind CSS, Styled-Components, responsive/mobile-first layouts
Tooling & Testing: Git & GitHub (branches, commits, pull requests), Jest, React Testing Library, Storybook, Webpack, Docker
Analytics & Tracking: Meta Pixel, Google Tag Manager (GTM), GA4, Microsoft Clarity, custom conversion-event tracking,
custom in-house analytics integration
Web3 (additional): Wagmi, RainbowKit, Viem

WORK EXPERIENCE
React Developer — Lazy Ants 2022 – Present
• Built and maintained a time-tracking application end-to-end: work-hour logging, report generation, and session management,
using React function components and hooks for state management.
• Developed a team analytics dashboard, rendering dynamic lists and data views with reusable, composable components.
• Built controlled forms for team-management features, including validation and multi-step flows.
• Integrated REST APIs for front-end/back-end communication, implementing loading states, error handling, and retry logic to
keep the UI responsive and reliable.
• Worked on Web3 features (deposit/withdrawal flows, smart-contract interactions) and an AI-driven market analysis feature.
• Optimized app performance, reducing load times and improving responsiveness.
• Wrote unit and integration tests with Jest and React Testing Library.
• Followed existing codebase conventions; participated in code review and pull-request workflows on GitHub, and mentored
junior developers.
• Set up and maintained tracking infrastructure — Meta Pixel, Google Tag Manager (GTM), GA4, and Microsoft Clarity —
configuring custom conversion events (e.g. tracking clicks on specific buttons like GoToCheckout, and precise form-
submission tracking), plus custom analytics integration through an in-house backend.
React Developer — Andersen Lab Jan 2022 – May 2022
• Contributed to a Spotify-style music streaming platform, focused on smooth UX and performance.
• Implemented audio playback, playlists, and user libraries with React and TypeScript, using controlled components and
hooks-based state.
• Integrated REST APIs for track metadata, authentication, recommendations, and playlist management, handling loading and
error states.
• Built responsive, accessible UI components and optimized the app for fast load times and lower memory use.
• Wrote unit and integration tests with React Testing Library to support reliability and maintainability.

LANGUAGES
Ukrainian — Native | English — Intermediate