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

Hi there! :)

I am Karol,

a software engineer.

a UI/UX designer.

a board game enthusiast.

a software engineer.

Projects

Logo of Web Image Editor
2026

Web Image Editor

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

Next.js
React
TypeScript
Prisma
TailwindCSS
PostgreSQL
Adobe Suite
Logo of AI Education Platform
2023

AI Education Platform

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

React
TypeScript
Vite
Zustand
TailwindCSS
Python
Figma
Logo of Collapp
2021

Collapp

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

Next.js
React
TypeScript
Prisma
Zustand
TailwindCSS
Node.js
Figma
Github
Logo of tic-tac-whoa
2019

tic-tac-whoa

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

React
JavaScript
Redux
Node.js
Adobe Suite
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 Suite
Additional Skills
Docker
AWS
GraphQL
React Native
Redux
Redux Saga
SASS
Cypress
Express.js
FastAPI
MongoDB
Python
C#
Kotlin
Balsamiq Wireframes
Visual Paradigm
Karol Sitarz © 2026