Сергей

Kushnerov Serhii
React Frontend Engineer
LinkedIn | [open contact info](look above in the "contact info" section) | @serhii_kushnerov | [open contact info](look above in the "contact info" section) | Panev■žys, Lithuania (EU
resident)

Summary
React Frontend Engineer with 3+ years of experience delivering scalable, high-performance web applications across Web3, e-
commerce, and enterprise proptech. Currently building AI-powered crypto trading infrastructure at Botty (Lithuania), with
hands-on expertise in Cursor AI and prompt engineering for accelerated development workflows. Proven track record: 40%+
reduction in page load times, 35% decrease in API overhead, and company-wide component libraries at JLL and ShipCheaper.
Master's degree in Software Engineering. Mentored junior developers at IT-Step Academy. Based in Lithuania (EU resident) ·
English B2 · Open to remote positions in EU and US markets.

Skills
Core: React.js, Next.js, TypeScript, Redux Toolkit, Redux-Saga, MobX, Zustand, GraphQL / Apollo Client
Libraries: TanStack Query, TanStack Table, React Virtual, React Router, React Hook Form, Formik, Zod, Yup
Styling: Tailwind CSS, SCSS/SASS, Material UI, Mantine UI, ShadCN, Radix UI, Styled Components, Framer Motion
Tooling: Webpack, Vite, Jest, Vitest, React Testing Library, Playwright, Storybook, CI/CD, Docker, Axios, ESLint, Node.js
AI & Dev Tools: Cursor AI, Prompt Engineering, GitHub Copilot
Practices: Git (GitFlow), Jira, Agile/SCRUM, SOLID, OOP, FSD, SEO, Compound Components, Figma

Experience (3+ years)
React Engineer | AI Workflow & Prompt Engineering (relocate on Europe ) Oct 2025 – May 2026
Botty Hybrid format was
Responsibilities:
• Building and optimizing core React/TypeScript UI for real-time trading dashboards, strategy configuration, and portfolio
analytics.
• Integrating AI workflows using Cursor AI and prompt engineering to accelerate feature delivery and improve code quality.
• Developing responsive, high-performance interfaces for complex financial data visualization (Web3 / crypto trading).
• Collaborating cross-functionally with backend and product teams in a fast-paced Web3 startup environment. Achievements:
• Implemented AI-assisted development practices (Cursor AI) that measurably improved development velocity across
the team.
• Delivered real-time trading UI with optimized state management and selective re-rendering for latency-sensitive data.

React Frontend Developer
Mar 2024 – Aug 2025 · 1 yr 6 mos
· Remote
ShipCheaper
Responsibilities:
• Led core frontend development of an e-commerce logistics platform using React, Next.js, and Redux to boost performance
and UX.
• Optimized UI with code splitting, memoization, and caching for faster loads and smoother interactions.
• Collaborated with backend, design, QA, and compliance teams to deliver features in an Agile environment.
• Integrated GDPR-compliant APIs for shipment tracking, rate calculation, and payment processing.
• Developed and maintained reusable, scalable, and accessible component libraries to support rapid feature delivery.
Achievements:
• Reduced checkout page load time by 42% through frontend optimization, improving conversion rates and user
satisfaction.
• Decreased API latency and frontend data usage by 35% with Redux and selective caching for real-time shipping rate
updates.
• Improved JavaScript execution by 36% via TypeScript enforcement, code audits, and optimizing high-traffic
components.
• Introduced code documentation and structured pull request templates, enhancing onboarding efficiency for new
developers.

React Frontend Developer Aug 2021 – Mar 2023 · 1 yr 7 mos
· Full-time
JLL
Responsibilities:
• Built reusable React components and responsive layouts for consistent UI across devices and global markets.
• Refactored legacy frontend into a modular, scalable React/TypeScript/Redux codebase, improving velocity and reducing tech
debt.
• Implemented token-based authentication with role-based access to secure client portfolios and property valuations.
• Delivered core features: dashboards, property filters, map browsing, and reporting tools in a 15+ person Scrum team.
• Integrated REST APIs (Node.js, Express) with PostgreSQL/MongoDB for property data, lease terms, and market analytics.
Achievements:
• Reduced production bug reports by 28% by introducing stricter unit testing standards and automated regression
checks.
• Improved application load speed by 34% using code-splitting, lazy loading, and optimized rendering for data-heavy
dashboards.
• Boosted developer productivity by ~20% by building a shared UI component library with Storybook, used across
regional portals.
• Accelerated feature delivery cycles by ~40% through a Storybook-driven workflow that cut QA feedback loops.
• Improved API performance by 24% using intelligent caching and Axios request batching for large property searches.

Education
Software Engineering — Master's Degree Sumy, Ukraine
SumDU

Mentorship
IT-STEP Academy: Mentored and taught Frontend Development (HTML, CSS, JavaScript, React), helping aspiring developers
build real-world skills and industry best practices. Nov 2023 – Jul 2025 · Part-time.