Олександр

Alexander Kutsenko
Senior Front-end Developer · React / TypeScript · Performance & Real-time UI
Kyiv, Ukraine · [відкрити контакти](див. вище в блоці «контактна інформація») · [відкрити контакти](див. вище в блоці «контактна інформація») · github.com/Alexkutsenko95 · [відкрити контакти](див. вище в блоці «контактна інформація»)
kutsenko95 · nextcv-pi.vercel.app · reel-five.pages.dev

SUMMARY

React and TypeScript developer with 9 years of commercial experience building and optimizing high-load web
applications — interfaces that stay responsive under a constant stream of real-time data, pixel-perfect from
Figma. Works in existing code bases as readily as in new ones: modernizing legacy front-ends onto current
React and optimizing rendering performance while the product stays in production. Built logistics and fleet-
management platforms rendering large live geodata sets on interactive maps, and real-time clients kept in sync
with the back end over WebSockets. Strong on performance profiling, architecture and state management;
runs code review and mentoring as a matter of course, and works across the Node.js back end. Most recently
shipped 8 real-time game titles to production on React, TypeScript, PixiJS and GSAP, together with the shared
component and business-logic libraries behind them.

TECHNICAL SKILLS

Core JavaScript (ES6+), TypeScript, HTML5, CSS3, SCSS
Front-end React (Hooks, Context), React Native, Redux, Redux-Saga, Zustand, MobX, Next.js
Real-time & graphics PixiJS, GSAP, WebSockets, deck.gl, OpenLayers
Back-end & APIs Node.js, Express, Socket.IO, REST APIs, Sequelize, Mongoose
Build & tooling Vite, Webpack, npm, yarn, ESLint, Prettier, Cloudflare Pages
UI styled-components, Material UI, React-Bootstrap, React Table, Formik, React Hook Form,
responsive layouts (desktop and mobile), pixel-perfect implementation from Figma
Performance performance optimization, profiling (Chrome DevTools, React Profiler), memoization,
virtualization, code splitting, bundle analysis
Testing Jest, Vitest, React Testing Library, Puppeteer (browser-driven suites)
AI coding tools Claude Code, Codex
Workflow Git, Bitbucket, Jira

EXPERIENCE

Senior Front-end Developer — Enjoy Gaming Apr 2024 – Aug 2026
React TypeScript Zustand PixiJS GSAP Vite WebSockets
Real-money gaming provider, regulated by the Isle of Man Gambling Supervision Commission. Team of 12.
Shipped 8 live game titles to production, plus 3 slot titles prepared for autumn 2026 release.
Tournaments — built the entire front end solo: a React 19 promo product layered over the whole game line, where
players compete inside a single title or across every game at once. Profiled render performance with the React Profiler
and optimized against those measurements.
Extracted the shared foundation behind the line: a React component library that reduced each new game to theming
and configuration, and a standalone business-logic library used by every title — bet placement and validation, payout
calculation and round state handling.
Animated game scenes with GSAP and PixiJS — wheel spins, lucky-number and multiplier reveals, win sequences —
rendered over the live video stream.
Implemented real-time synchronization with the game server over WebSockets, keeping the client — betting window,
results, payouts — consistent with the live round under packet loss and reconnects.
Profiled and optimized the render loop — per-frame allocations, texture memory and scene complexity — holding 60 fps
under the live data stream, with quality scaled down on weak devices.
Owned client-side state architecture on Zustand and migrated the build pipeline to Vite.
Reviewed code and mentored teammates across the front-end team throughout, keeping the shared libraries refactored
as the individual games diverged.
Front-end Developer — Inoxoft Apr 2021 – Apr 2024
React Redux Redux-Saga TypeScript Webpack deck.gl OpenLayers
Software outsourcing company; worked on freight-delivery and fleet-management platforms for the UK market.

Delivered logistics applications on React + TypeScript for freight deliveries across the UK — from requirements to
production support, working directly with the clients; built the UI responsive for desktop and mobile, pixel-perfect to the
Figma designs.
Built interactive map interfaces for route planning, fleet and shipment tracking using deck.gl and OpenLayers, and
optimized them to render large sets of live geodata without dropping frames — profiling re-renders, memoizing selectors
and throttling live updates.
Implemented complex asynchronous flows with Redux-Saga — long-running requests, retries and live tracking streams
— and delivered a second logistics product for a different client, under NDA.
Modernized inherited legacy React code as a routine part of the work: class components rewritten to hooks, expensive
renders memoized, and a clear split between container and presentational components — refactoring in place, without
pausing feature delivery.
Ran code review and mentored junior developers as a constant part of the role; took part in estimation and planning.

Earlier experience — Front-end / Full-stack Developer May 2017 – Mar 2021
React React Native Redux Redux-Saga Redux-Thunk MobX Next.js Express Socket.IO Jest
Zazmic, ORTY IO, JS Dynamics, freelance, Onnisoft, Starthubit and Big Data Hush — product and outsourcing teams where the
React and Node.js foundation was built.
Shipped web and cross-platform mobile interfaces from a shared React / React Native codebase, including offline and
error states on mobile.
Built the player-facing client of a licensed online casino running third-party game providers — lobby, betting UI and
account screens — plus the back office it was operated from, and integrated a sports provider's live match streams on
both sides: in-play betting for players, and the same feed in the back office, where a match could be blocked from the
site.
Delivered full-stack features on React with a Node.js / Express back end and real-time updates over Socket.IO, covered
the front-end with Jest unit tests, and maintained and refactored legacy front-ends across product and outsourcing
teams alongside feature work.

SELECTED PROJECTS

Reel Five — 5×3 slot machine, personal project reel-five.pages.dev
React 19 TypeScript PixiJS 8 GSAP Zustand Vite Vitest
A PixiJS scene and a React interface sharing one store — built to show the canvas side of the stack on its own, end to end and in
production shape.
PixiJS renders the reels imperatively, React owns the interface, and a single zustand store — created in the React app
and handed down into the scene — is the only source of truth: the reels never touch the balance, they replay a result the
store has already decided.
Reel stop is a state machine — staggered starts and stops, velocity kept continuous across the hand-off from spin to
settling tween, anticipation on the last reels, and motion blur applied only while a reel is actually moving.
20 paylines with wild substitution; reel strips tuned by simulation to a 95.97% RTP over 1,000,000 spins, reproducible
from the repository.
118 tests across three suites — engine and store in Node, React components in jsdom, and the Pixi scene plus the
whole app driven in a real Chrome; the browser suite caught two defects the other two could not reach. Ukrainian and
English interface, and no binary assets — every symbol is drawn in code and baked into a texture at start-up.

Penalty & Free kick — two football games on one kutsenko-penalty.pages.dev · kutsenko-free-kick.pages.dev
engine, personal projects
React 19 TypeScript PixiJS 8 Zustand Vite Vitest Cloudflare Pages
Two separate games built on a shared source layer — projection, ball physics, goalkeeper, goal frame, input model, layout shell and
localization live in one place and are consumed by both.
The ball flies by numerical integration rather than a shaped curve: quadratic drag including the drag crisis, Magnus lift
derived from the spin ratio ωr/v, spin decay, and wake instability for a ball struck without spin. Aiming survived that
change because the launch is solved rather than authored — a two-point boundary-value problem, shooting method
with a numerical Jacobian — so the player still aims at a point while the flight stays physical.
Where you strike the ball sets the spin axis directly (r × v), and the goalkeeper is bounded by hand speed rather than a
fixed dive time; conversion was measured over 200-seed sweeps rather than tuned by feel. 126 tests in Node, including
a search proving every generated level is beatable on all four difficulty modes.

EDUCATION & LANGUAGES
National Transport University (NTU) — PhD, Software Engineering · 2018 – 2024
Kyiv State Maritime Academy (KDAVT) — MSc, Software Engineering · 2016 – 2018
GoIT — Java SE / Java EE course · 2015 – 2016
Ukrainian — native · English — B2 (Upper-Intermediate)