photo of an arm holding a smartphone with a web application open on it
a digital sketch of an arm holding a smartphone with a web application open on it
a vector illustration of an arm holding a playing card - ace of clubs

Good evening :)

I am Karol,

a software engineer.

a UI/UX designer.

a board game enthusiast.

a software engineer.

Projects

Logo of Web Image Editor

Web Image Editor

2026

A creative platform featuring a proprietary canvas rendering system, designed with a focus on UX and community oriented features.

Logo of AI Education Platform

AI Education Platform

2023

AI-powered learning platform that enables teachers to create personalized interactive trainings from their own study materials.

Logo of Collapp

Collapp

2021

Real-time collaboration spaces for regular users, hassle-free plugin development tools for external developers.

Github
Logo of tic-tac-whoa

tic-tac-whoa

2019

"Tic-tac-toe", but eight times more challenging. Two-player real-time online game.

Github

About

profile picture of Karol Sitarz

My name is Karol Sitarz.

I am a Senior Software Engineer with a strong eye for UI/UX and passion for user-focused design. My expertise lies in transforming complex domain logic into intuitive, elegant products.

Primary Expertise
React
Next.js
TypeScript
JavaScript
Zustand
TailwindCSS
Node.js
REST
Prisma
SQL
Jest
Playwright
Web Accessibility (a11y)
Git
Vite
Figma
Adobe Photoshop
Adobe Premiere
Additional Skills
Docker
AWS
GraphQL
React Native
Redux
Redux Saga
SASS
Cypress
Express.js
FastAPI
MongoDB
Python
C#
Kotlin
Adobe Illustrator
Adobe InDesign
Balsamiq Wireframes
Visual Paradigm
Karol Sitarz © 2026