Олег

OleG I.
Senior Front-end Engineer

SUMMARY

I’m a front-end developer with over 10 years of professional experience, with the
last 5 years focused primarily on React and its ecosystem. My core stack includes React,
Next.js, and TypeScript, and I specialise in building scalable, responsive, and accessible
user interfaces, including advanced UI animations and micro-interactions implemented
with GSAP, Anime.js and Framer Motion.

SKILLS / COMPETENCIES

Programming Languages: JavaScript, TypeScript, HTML, CSS, SASS/Less
Technologies: React.js, Next.js, Axios, tanstack-query, Valtio, Zustand, Redux, RTK, WebSocket,
RESTful API, styled-components, Tailwind, Shadcn/ui, MUI, Bootstrap, GSAP, Vite, Vitest, Jest,
React Testing Library, AJAX, jQuery
Tools: Figma, Sketch, Zeplin, Adobe Photoshop, Postman
Familiar with CMS: Magento, WordPress, Shopify
Source Control: Git (Gitlab/Github/Bitbucket)
Tracking Systems: Jira/ClickUp/Notion
Development Methodologies: Scrum, Agile

LANGUAGE

English - Intermediate (B1+)
Ukrainian - Advanced (С1)
WORK EXPERIENCE

P2H (September 2011 – 2024)

Markup developer (Junior → Senior)
2011 – 2014

Description:
Translated designer mockups into semantic, pixel-perfect HTML structures, ensuring consistency
with branding guidelines and accessibility best practices.

Responsibilities:
● Architected modular stylesheets using CSS, SASS, and LESS with BEM conventions, reducing
duplicated code and speeding up style maintenance.
● Implemented interactive UI components (carousels, modals, dropdowns, form enhancements)
using vanilla JavaScript, jQuery, improving user engagement and feature reuse.
● Implemented responsive layouts and cross-browser fixes (IE6+ through modern), delivering a
unified experience across desktop, tablet, and mobile.
● Optimised front-end performance by minifying assets, inlining critical CSS, deferring non-essential
scripts, and leveraging image sprites.
● Championed code reviews, mentored two junior developers, and established frontend coding
standards that improved team velocity and code quality.

Front-end developer (e-commerce)
2015 – 2018

Description:
Development of online stores and turnkey webshops, delivering responsive, SEO-optimised experiences
across Magento, WooCommerce, and Shopify.

Responsibilities:
● Customised responsive, SEO-optimised themes for Magento v1/2.
● Developed UI for the WordPress themes and WooCommerce storefronts.
● Implemented and customised Shopify themes using Liquid, JavaScript, and SASS, integrating
apps.
● Optimised front-end performance through asset minification, lazy loading, code splitting, and
image compression.
● Ensured cross-browser compatibility (IE10+ through modern) and mobile-first responsiveness,
performing manual QA across devices.
● Collaborated with design and backend teams.
Front-end developer (React)
2019 – 2024

Project:
Created a responsive, feature-rich online teaching platform empowering instructors to deliver
interactive lessons, track student progress, and enrich practice sessions.

Tech stack: React, Axios, MobX, formik + yup

Responsibilities:
● Developed core UI components in React, enabling dynamic lesson playback, notation overlays,
and customizable practice loops.
● Managed complex application state (lesson sequences, student progress, playback settings) in
MobX stores for predictable, real-time updates without prop drilling.
● Designed a scalable SASS architecture with theming variables and responsive mixins, ensuring
brand consistency and pixel-perfect layouts across devices.
● Integrated HTML5 API to support loop, metronome, and pitch-shift features, boosting student
engagement and practice efficiency.
● Collaborated closely with backend engineers to define API.

Project:
Developed a responsive, SEO-optimised web application for showcasing premium chocolate
collections and interactive tasting guides.

Tech stack: Next.js (v10), MobX, Formik + Yup, Firebase

Responsibilities:
● Architected server-side rendering with Next.js v10 to ensure fast first-byte times and optimal
crawlability.
● Modelled complex UI state in MobX stores for instant and prop-drill-free updates.
● Built a modular SASS architecture with component-scoped and global theming, delivering
pixel-perfect designs across mobile, tablet, and desktop.
● Integrated Firebase to store results without a custom backend.
● Crafted accessible forms using Formik with Yup validation, achieving zero drop-off on
submissions.
● Implemented GDPR-compliant cookie consent and integrated Google Analytics, balancing user
privacy with actionable insights.
● Optimised bundle size through code splitting and lazy loading, maintaining page loads well.
● Partnered with designers to translate Figma prototypes into pixel-perfect UIs.
Project:
Built a subscription platform that sells access to reusable API products, enabling clients to
subscribe, manage keys, and integrate those APIs into their own applications.

Tech stack: React, Axios, Tanstack Query, Valtio, Styled Components, React Hook Forms + Zod, Vitest,
Playwright, Storybook

Responsibilities:
● Designed and implemented a reusable component library with consistent theming and
accessibility-ready patterns to accelerate feature delivery and ensure visual parity across the app.
● Implemented robust client-side integrations with backend services for subscription lifecycle, billing
calculations, API key provisioning, and usage reporting, including optimistic UI updates and
graceful error handling for network failures.
● Developed comprehensive E2E test suites with Playwright covering critical flows: signup,
subscription purchase, API key issuance, and usage reporting to prevent regressions in
production. Wrote unit and integration tests with Jest and React Testing Library, driving codebase
coverage above 80% and ensuring high confidence for refactors and CI pipelines.
● Employed code-splitting and lazy loading for modules to reduce initial bundle size and improve
Time to Interactive. Implemented caching and incremental data fetching strategies to keep
dashboard latency low under concurrent load.
● Collaborated closely with backend engineers on API contracts and pagination, partnered with
designers to convert Figma prototypes into pixel-perfect, responsive pages, and participated in
sprint planning and code reviews to maintain engineering standards.

Whales Marketing (November 2024 – 2025)

Front-end developer

Project:
Built a responsive, SEO-friendly UI for a WordPress-based corporate website, translating Figma
designs into pixel-perfect templates and reusable theme components using GSAP for interactive
elements.

Tech stack: HTML, CSS, JavaScript, GSAP, Anime.js, PHP (modify templates)
Project:
Built a responsive AI assistant interface with support for uploading documents and submitting web
links as context sources for assistant answers.

Tech stack: React, Axios, Tanstack Query, Valtio, Shadcn/ui, Tailwind, React Hook Forms + Zod

Responsibilities:
● Implemented streaming chat UI with editable messages, conversation history, and session
controls (new, rename, pin, delete). Added document and URL upload flows so users can supply
files and web links that the assistant uses to answer context-aware queries.
● Managed server-synced data with TanStack Query and Axios; used Valtio for local reactive UI
state.
● Assembled accessible, themeable components with shadcn UI and defined light/dark design
tokens.
● Optimised for performance with code-splitting and virtualisation for long message lists; added
retry and offline fallbacks.
● Delivered hooks and small component library for easy extension and fast feature work.

Hybrid (November 2025 – May 2026)

Front-end developer

Tech stack: HTML, CSS, TypeScript, JavaScript, GSAP, Shopify (APIs & Checkout Extensions), Liquid,
PHP (modify templates), React ecosystem, Tailwind

Responsibilities:

● Developed and customised solutions on Shopify and Webflow platforms.
● Implemented custom functionality in Shopify, working with platform APIs.
● Built and maintained frontend components for WordPress projects.
● Engineered web applications using React and TypeScript.
● Designed and delivered a Shopify Checkout Extension to enhance purchasing workflows.
● Collaborated closely with design and backend teams to deliver integrated web solutions.
● Enhanced user interfaces and optimised performance for improved user experience.

EDUCATION

2009
Simon Kuznets Kharkiv National University of Economics
Master’s degree in “Information Management Systems and Technologies”