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Sławomir Mazgaj

Senior Software Developer

15+ years crafting interactive experiences — from Flash games engines to enterprise SaaS, adaptive learning platforms and VR

About.

London, UK 15+ years experience

I'm a Senior Software Developer with over 15 years of professional experience building interactive, high-performance web applications. My career spans from game development at Gamesys to enterprise SaaS platforms and adaptive learning technology.

I specialize in React, Next.js, and TypeScript, with deep expertise in PixiJS, Three.js and real-time graphics. I'm passionate about creating smooth, accessible user experiences that combine technical precision with thoughtful design.

Master of Science in Engineering

West Pomeranian University of Technology, Szczecin, Poland

Computer Science & Information Technology, Multimedia Methods

Thesis: “HDR tone mapping which incorporates observer's point of gaze”

Experience.

15+ years of building interactive experiences across gaming, enterprise, and education.

Senior Front End Developer

OBRIZUM

Developing an adaptive learning platform that empowers mission-critical learning with measurable impact.

  • Working on big rewrite of user-facing portal and CMS from ClojureScript to Next.js
  • Adding 360 video player for Web and VR
Next.js
TypeScript
React Query
Tailwind
shadcn/ui
Three.js
AWS Amplify

Senior Software Engineer

Simpplr · Employee Listening

Delivering real-time employee sentiment analysis and actionable insights to improve the employee experience.

  • Creating brand-new survey product (creation, participation, reporting)
  • Maintaining existing sentiment check product
  • Added more endpoints and deployed serverless applications using AWS Lambda
  • Added Mixpanel integration
React
TypeScript
React Query
React Testing Library
CSS Modules
Micro-frontends
AWS Lambda
Serverless
Nivo

Front End Developer

Yoti · Yoti Sign

Worked on a document signing platform.

  • Added multiple core features: Wet signature, Pre-filled text fields, Twilio integration
  • Contributed to cross-team shared React component library
  • Replaced all Enzyme tests with React Testing Library
React
Hooks
Context API
GraphQL
React Testing Library
Enzyme
Gatsby

Senior Developer

Gamesys · Core Tech

Worked on various web development projects.

  • Built a tournament prototype with Heroic Labs / Nakama server integration
  • Maintained Game UI used across all internal Game Studios
  • Created page for displaying analytics data pulled from Splunk
React
JavaScript ES6
Node.js

Senior Developer

Gamesys · Social Gaming

Helped with big mobile game lobby rewrite (for JPJ Slots).

React Native
TypeScript
Redux
RxJS

Senior Developer

Gamesys · Game Studio

Worked on internal libraries so other devs could build games on top of them.

Haxe
PixiJS
Spine
Howler
Waud

Senior Game Developer

Gamesys · Social Gaming

Worked on refactoring existing game lobby (JPJ Slots) on web.

  • Internal "Abstraction View" framework was created to provide single codebase for web and mobile
  • Lobby was white-labeled so it could be provided for different vendors

Lead Developer

Gamesys · Social Gaming

Lead development of Android version of Bingo Lane.

Adobe AIR
Starling
ANE

Game Developer

Gamesys · Social Gaming

Worked on soft-core MMORPG game (Here Be Monsters) on Facebook platform.

Flash
Pure MVC
Graph API
Google Maps

Junior Game Developer

Game Factory

  • Worked on 17 game projects (in more than half as the only developer)
  • Moved to Social Team where they worked on big Facebook games (for Wooga) such as Brain Buddies, Monster World, and Diamond Dash
Flash
Pure MVC
Graph API

Skills.

Technologies and tools I work with regularly.

Frontend

React
Next.js
React Native
Hooks
React Query
React Testing Library
Gatsby

Languages

TypeScript
JavaScript
HTML
CSS
Haxe
ClojureScript

Styling

Tailwind CSS
shadcn/ui
CSS Modules
Styled Components

State & Data

React Query
Context API
Redux
RxJS
GraphQL
RESTful API

3D & Graphics

Three.js
PixiJS
Spine
WebXR / VR
Flash / AS3

Backend & Cloud

Node.js
AWS Lambda
AWS Amplify
Serverless

Tools & Workflow

Git
GitHub Actions
Micro-frontends
Mixpanel
Splunk

Projects.

Personal and side projects showcasing different technologies.

Projects coming soon

I'm currently curating my best work to showcase here. Check back soon!