Rails programmer open to different technologies. Expert in unsolvable challenges. Passionate gamer, game creator and regular participant of Global Game Jam. Constantly developing skills related to image analysis and neural networks.


Backend &Frondend Development Application Architecture API Design Refactoring Visualization

Global JSON Invoicing Standard

An open-source project written in Go, standardizing global electronic invoicing with JSON. It simplifies document creation, ensures compliance with local regulations, and fosters seamless electronic business communication. With a JSON Schema, library, and global tax database, GOBL streamlines the invoicing process for developers. The project emphasizes a practical and standardized approach to electronic business document exchange.

Major contributions

  • JSON to KSeF structure converter (Go)
  • JSON to XRechnung structure converter (Go)

E-commerce platform for ordering drinks with fast delivery (up to 3 hours) in an eco-friendly way. Service is available to individuals and businesses. From ordering to delivery to picking up empty bottles and reordering, the entire supply chain is supported. Frontend application in Next.js and onion architecture under the hood. Microservices built on Sinatra and powered by Apache Kafka.

Major contributions

  • Development in Sinatra (Ruby)
  • Customer Accounts Authentication service
  • React frontend development (Next.js)

A simple game based on augmented reality. The goal is to explore the former circus base and learn while having fun. Technologically, the game is based on Unity engine and written in C#. It is a free download from the Apple Store, but requires AR markers, which are available in Julinek Park.

Major contributions

  • Development in Unity
  • Bugs resolving
  • Submitting to the App Store

Global learning platform offering online courses from universities worldwide. Over 19 million users, thousands of courses in dozens of industries. Partners (universities, organizations, industry partners, and government partners) create different types of courses in the app. These include MOOCs (Massive Open Online Courses), ExpertTrack, microcredentials, and degrees. Technologically, the application is a Rails monolith with a React frontend.

Major contributions

  • Development in Ruby on Rails
  • User conversion experiments
  • GDPR compliance tools
  • Frontend development in React

Management business with no paperwork. Customer service, create invoices, order management. All in one place, easy-to-use and painless. Available API in standard JSON API (in progress).

Major contributions

  • Backend development in Ruby on Rails
  • Integration with polish e-Invoicing (Polish KSeF)
  • Updating Rails to version 7.x
  • Implementation of importmaps
  • Updating Bootstrap 3 to Bootstrap 5
  • Frontend development in Ember.js
  • Create documentation using Swagger

This is our company website. It shouldn't be complicated. The task of this site is to show what and how we do. We work on it in our free time. The project is public and anyone can look at the code.

Major contributions

  • Updating Rails to version 7.x
  • Implementation of importmaps
  • Updating Bootstrap 3 to Bootstrap 5

Major contributions

  • Configuration and administration
  • Copywriting

Application supporting design hand-made ceramic tiles. Users can choose the shapes, patterns and colors. Ordering process is a multi-step and requires an individual valuation, because the tiles are manufactured by hand.

Major contributions

  • Backend development in Ruby on Rails
  • Bugs resolving
  • Deployment to staging

based on microservices

Collaborative web-based platform for idea management. It allows to empower people to gather ideas but also process them in a creative, productive and simple way. Based on the methodology CPS 6.1 (Creative Problem Solving).

Major contributions

  • Backend development (Ruby on Rails, Cordova)
  • Developing Cordova application
  • Frontend development (Ember.js)
  • Developing microservice architecture
  • Developing API

linguistic analysis

Linguistic analysis system is used for word processing and automatic category detection. The application can also detect the language of the text. The database contains over 6 million words in Polish and English. The system has a learning mode with a teacher and the categorization is based on statistical methods. Application provides an external API.

Major contributions

  • Backend development in Ruby on Rails

20 questions game

Logic game which learns with every play. In the game you have to answer questions asked by the AI and it will try to guess what were you thinking about.

Major contributions

  • Backend development in Ruby on Rails
  • Frontend development
  • Designing and implementation of the game logic
  • Implementation of an administration panel
  • Database design
  • Writing unit and acceptance tests
  • Creating translations
  • Taking care of framework updates
  • Designing zero state application

Backend development

  • Ruby on Rails
  • Ruby
  • Python
  • C#
  • Sinatra


  • PostgreSQL
  • MySQL
  • SQLite

Frontend development

  • JavaScript
  • TypeScript
  • ®Ember.js
  • CoffeeScript
  • React
  • Next.js

Web technologies

  • HTML5
  • CSS3
  • Sass
  • Slim Template Language
  • BootstrapBootstrap


  • RSpec
  • Jest
  • Playwright
  • Selenium WebDriver


  • Git
  • docker
  • GitHub
  • Apache Kafka
  • Terraform

Game development

  • Unity
  • three.js

Mobile development

  • Apache Cordova

Search engine

  • Apache Solr
  • Elasticsearch
  • OpenSearch

Operating systems

  • Ubuntu
  • Apple

Cloud Computing

  • Google Cloud
  • Heroku

Mathematical software


Project management software

  • Trello
  • Taiga

Linters &code formatters

  • RuboCop
  • ESLint
  • Prettier

CI (Continuous Integration)

  • GitHub Actions
  • Jenkins