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Oleh Kolisnyk

@olehkolisnyk

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Senior React / Next.js engineer focused on complex web apps, frontend performance, and maintainable architecture.

Ukraine

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What I'm looking for

I’m open to remote product teams and engineering-focused companies where frontend quality and ownership matter.

I've built production React and TypeScript features for Songer, an AI music generation platform, including a multi-step generation flow, persistent state, and reliable WebSocket synchronization.

Across complex React applications, I've improved frontend performance, stabilized state management, translated Figma designs into reusable interfaces, and refactored codebases that had become difficult to maintain. On one project, performance work raised Lighthouse scores from 30 to 96 on mobile and from 40 to 99 on desktop.

I have 10+ years in web development and 8+ years focused on React. My main stack includes React, Next.js, TypeScript, Tailwind CSS, Redux, Zustand, TanStack Query, and REST API integration. I work comfortably with backend, QA, design, and product teams and can own frontend features from implementation through production.

Experience

Work history, roles, and key accomplishments

Frontend Developer

Songer

Mar 2025 - Feb 2026 (11 months)

Built a multi-step song generation flow with shared state, resolved WebSocket sync issues, and refactored components to reduce re-renders. Developed production features for an AI music platform using React and TypeScript.

React TypeScript Zustand WebSockets Figma

Independent Web Developer

Upwork

Jan 2022 - Feb 2025 (3 years 1 month)

Improved Lighthouse scores from 30 to 96 on mobile and 40 to 99 on desktop, fixed performance bottlenecks in a React/Next.js chat app, and built a SaaS product for a long-term clients. Maintained a 100% Job Success Score and 5.0 ratings.

React Next.js Performance Optimization TypeScript

Frontend Developer

Byzantium Agency

Jul 2020 - Jan 2022 (1 year 6 months)

Built and maintained frontend interfaces for e-commerce and marketing projects using Tailwind CSS, Alpine.js, Twig, and Laravel Blade. Translated Figma designs into production-ready templates.

Tailwind Twig Laravel Figma

React Developer

Travel Booking Startup (NDA)

Jan 2019 - Jan 2020 (1 year)

Developed core tour catalog and detail flows for an international travel booking platform using React and Redux. Built reusable UI components with Ant Design.

React Redux Ant Design

React Developer

SocialDeals

Jan 2018 - Jan 2019 (1 year)

Built the landing page and main dashboard for a blockchain wallet platform using Next.js. Implemented Firebase-based authentication and real-time data functionality.

Next.js Firebase Authentication

HTML/CSS Developer

Riverbranch LLC

Jan 2017 - Jan 2018 (1 year)

Developed and maintained responsive HTML/CSS/SCSS templates for corporate, landing, and e-commerce projects. Fixed frontend bugs and refactored legacy styles.

HTML CSS SCSS