Oleksander Haivoronskyi - Front-End Application Developer

Q: Where is Oleksander based?

Oleksander is based in Kyiv, Ukraine .

Q: What languages does Oleksander speak?

Oleksander speaks the following languages: Ukrainian (Native), English (Advanced) .

Q: How many years of experience does Oleksander have?

Oleksander has at least 13 years of experience. During this time, Oleksander has worked in at least 4 different roles and for 4 different companies . The average length of individual experience is 3 years and 3 months . Note that Oleksander may not have shared all experience and actually has more experience.

Q: What is Oleksander's latest experience?

Oleksander's most recent position is Front-End Application Developer at Pekarium .

Q: What companies has Oleksander worked for in recent years?

In recent years, Oleksander has worked for Pekarium .

Q: Which industries is Oleksander most experienced in?

Oleksander is most experienced in industries like Banking and Finance , Media, Entertainment and Publishing , and Information Technology (IT) .

Q: Which business areas is Oleksander most experienced in?

Oleksander is most experienced in business areas like Information Technology (IT) and Product Development .

Q: Which industries has Oleksander worked in recently?

Oleksander has recently worked in industries like Banking and Finance .

Q: Which business areas has Oleksander worked in recently?

Oleksander has recently worked in business areas like Information Technology (IT) and Product Development .

Recommended expert

Kyiv, Ukraine

Experience

Jan 2019 - Present

7 years 2 months

Kyiv, Ukraine

Front-End Application Developer

Pekarium

Built a WebGL-based single-page trading platform for desktop web, mobile web, and iOS WebView integration.
Engineered a custom data-visualization tool with infinite zoom, variable detail levels, and multiple rendering modes.
Implemented custom Three.js renderers, GLSL shaders, and procedural mesh generation for real-time data.
Designed flexible architecture supporting data from network streams and mathematical models.
Added annotation layers, interactive chart tools, and random data simulation features.
Collaborated with backend engineers for WebSocket-based real-time data sync.
Integrated React Hooks, Context API, and dynamic component loading for modular UI.
Reduced rendering latency by ~30% through memory profiling and frame budget tuning.
Integrated Unreal WebSockets for real-time PVP communication with Node.js server.
Built reusable combat systems and in-game debug tools to accelerate testing.
Managed multi-environment builds and CI/CD pipelines with Docker and GitHub Actions.
Mentored junior developers and reviewed pull requests for code quality and standards.

Jan 2016 - Dec 2019

4 years

Lead Game Developer (Unreal Engine 4)

Monolith Mind

Led client-side development of an online collectible card game built in UE4.
Created the full battlefield UI and combat logic using Blueprints and C++.
Implemented ECS pattern for modular game systems and network sync.
Collaborated with design and art teams to integrate VFX and animations without performance drops.
Optimized CPU/GPU bottlenecks and reduced draw calls by 25%.
Established version-controlled pipelines using Perforce and Git.
Delivered fully functional battle prototype within six months for QA testing.
Coordinated cross-disciplinary workflow between Unreal and web teams.

Jan 2015 - Dec 2016

2 years

Kyiv, Ukraine

JavaScript Game Developer

PrivateDev

Developed a minimalistic JavaScript game engine using PIXI.js and Howler.js.
Ported multiple gambling titles to the engine with optimized mobile and desktop performance.
Implemented custom event bus and game loop patterns for real-time updates.
Applied object-oriented design principles for reusability and maintainability.
Integrated touch controls, sound management, and resource loading systems.
Designed debugging interfaces for testing game logic and physics.

Jan 2013 - Dec 2015

3 years

Kyiv, Ukraine

Front-End Developer

Freelance

Delivered interactive web projects for local clients using HTML, CSS, and vanilla JavaScript.
Created a Match-3 browser game prototype using Canvas and DOM manipulation.
Experimented with game loops, collision detection, and render optimization.
Implemented responsive layouts for multi-device compatibility.

Industries Experience

See where this freelancer has spent most of their professional time. Longer bars indicate deeper hands-on experience, while shorter ones reflect targeted or project-based work.

Experienced in Banking and Finance (7 years), Media and Entertainment (4 years), and Information Technology (4 years).

Banking and Finance

Media and Entertainment

Information Technology

Business Areas Experience

The graph below provides a cumulative view of the freelancer's experience across multiple business areas, calculated from completed and active engagements. It highlights the areas where the freelancer has most frequently contributed to planning, execution, and delivery of business outcomes.

Experienced in Information Technology (13 years) and Product Development (11 years).

Information Technology

Product Development

Summary

Software Engineer with 8 + years of experience developing high-performance applications across web, data-visualization, and game engine domains. Specialized in JavaScript (ES6 +), React, Node.js, and WebGL, with expertise in rendering optimization, scalable architecture, and interactive UI/UX.

Strong record of delivering cross-platform systems that run efficiently on desktop, mobile, and embedded devices. Passionate about clean architecture, real-time performance, and exploring the intersection of web and 3D graphics.

Expert in React.js / Node.js / Three.js / TypeScript development
Skilled in real-time visualization and custom shaders
Proven ability to design and optimize complex front-end architectures
Excellent debugging, profiling, and CI/CD automation skills
Strong team collaboration and Agile experience

Skills

Languages

Javascript (Es6 +)
Typescript
C ++
Glsl

Frontend

React.js
Webgl
Three.js
Html5
Css3

Graphics & Rendering

Three.js
Pixi.js
Unreal Engine 4
Game Loop Pattern

Backend

Node.js
Express.js
Websockets

Tools & Systems

Git
Docker
Webpack
Figma
Jira
Vs Code

Databases

Mongodb
Postgresql

Workflow

Agile
Scrum
Kanban

Testing & Optimization

Jest
Chrome Devtools
Performance Profiling

Languages

Ukrainian

Native

English

Advanced

Education

Sep 2011 - Jun 2015

Donetsk National Technical University

Bachelor’s Degree in Technical Information Security (Radioelectronics) · Technical Information Security (Radioelectronics) · Donetsk, Ukraine

Profile

Created

November 2025

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Frequently asked questions

Do you have questions? Here you can find further information.

Where is Oleksander based?

Oleksander is based in Kyiv, Ukraine.

What languages does Oleksander speak?

Oleksander speaks the following languages: Ukrainian (Native), English (Advanced).

How many years of experience does Oleksander have?

Oleksander has at least 13 years of experience. During this time, Oleksander has worked in at least 4 different roles and for 4 different companies. The average length of individual experience is 3 years and 3 months. Note that Oleksander may not have shared all experience and actually has more experience.

What roles would Oleksander be best suited for?

Based on recent experience, Oleksander would be well-suited for roles such as: Front-End Application Developer, Lead Game Developer (Unreal Engine 4), JavaScript Game Developer.

What is Oleksander's latest experience?

Oleksander's most recent position is Front-End Application Developer at Pekarium.

What companies has Oleksander worked for in recent years?

In recent years, Oleksander has worked for Pekarium.

Which industries is Oleksander most experienced in?

Oleksander is most experienced in industries like Banking and Finance, Media, Entertainment and Publishing, and Information Technology (IT).

Which business areas is Oleksander most experienced in?

Oleksander is most experienced in business areas like Information Technology (IT) and Product Development.

Which industries has Oleksander worked in recently?

Oleksander has recently worked in industries like Banking and Finance.

Which business areas has Oleksander worked in recently?

Oleksander has recently worked in business areas like Information Technology (IT) and Product Development.

What is Oleksander's education?

Oleksander holds a Bachelor in Technical Information Security (Radioelectronics) from Donetsk National Technical University.

What is the availability of Oleksander?

Oleksander is immediately available full-time for suitable projects.

What is the rate of Oleksander?

Oleksander's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.