Joanna Patrzyk, Developer in Kraków, Poland
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Joanna Patrzyk

Verified Expert  in Engineering

Software Developer

Kraków, Poland
Toptal Member Since
November 29, 2019

Joanna is a software engineer with over eight years of experience in programming. She specializes in building full-stack JavaScript solutions, including Node.js, TypeScript, React, and React Native. Joanna is highly skilled in building quality web, mobile, and PWA apps.


Software Mansion
i18n, PostgreSQL, Jest, Redux, Git, Unix, Relay, GraphQL, Phoenix, Elixir...
Branchspace (via Software Mansion)
Amazon Web Services (AWS), Material Design, Redux-Saga, i18n, Java, Jest...
Branchspace (via Software Mansion)
Amazon Web Services (AWS), Material Design, Redux-Saga, i18n, Java, Jest...




Preferred Environment

IntelliJ IDEA, WebStorm, Git, MacOS

The most amazing...

...project I've coded is a quantum computer simulator able to solve the integer factorization problem using Shor's algorithm.

Work Experience

Senior Software Engineer and Team Lead

2017 - 2019
Software Mansion
  • Worked for a startup client on a community-leveraged platform for job seeking. I led a small remote team that rewrote a mobile app from Android to React Native.
  • Collaborated on a React Native eCommerce boutique app. I guided the team during the migration to TypeScript. I also repaired and redesigned the build configuration for Android.
  • Developed full-stack features in an internal project with Elixir as the back end (Phoenix, Ecto, Absinthe and PostgreSQL), serving GraphQL API, and React with a Relay front end. The system was used internally for employee and project management and time tracking.
  • Assisted in the recruitment process and conducted technical interviews.
  • Conducted workshops about React Native and Expo.
Technologies: i18n, PostgreSQL, Jest, Redux, Git, Unix, Relay, GraphQL, Phoenix, Elixir, Spring, Java, Expo, React Native, React, TypeScript, JavaScript

Senior Software Developer and Front-end Team Lead

2017 - 2018
Branchspace (via Software Mansion)
  • Participated as part of an Agile team to develop a highly customizable digital platform for airlines and the travel industry.
  • Led the front-end team, set up and maintained our React apps.
  • Worked on the back end (Java 8, Spring), developing the REST API.
  • Integrated Redis for session management which greatly improved the scalability of the system.
Technologies: Amazon Web Services (AWS), Material Design, Redux-Saga, i18n, Java, Jest, JavaScript, Git, Unix, Jenkins, Redis, MongoDB, Spring, Java 8, Webpack, Sass, Redux, React

Senior Software Developer

2016 - 2017
Branchspace (via Software Mansion)
  • Worked in a small Agile team on CRUD apps for company data management for the airline and travel industry, using Shibboleth for Single Sign-On.
  • Focused on the front-end development of a React app, and helped on the back end using Java, Spring, and Hibernate.
Technologies: Amazon Web Services (AWS), Material Design, Redux-Saga, i18n, Java, Jest, JavaScript, Redux, Git, Unix, Jenkins, Shibboleth, Oracle Database, Hibernate, Spring, Java 8, Sass, Material UI, React

Senior Software Engineer

2015 - 2017
Software Mansion
  • Worked for a variety of clients, primarily using React, Node.js, Java, and Android SDK.
  • Assisted in the development of an embeddable web chat widget utilizing CanJS and Node.js.
  • Developed projects in several different business domains, including the airline and travel industry, home automation, and product and campaign management.
Technologies: JavaScript, Git, Unix, Java, Node.js, CanJS, React

Android Developer

2016 - 2016
Node1 (via Software Mansion)
  • Built a simple native Android app for Home Automation, including integration with the Uber API.
Technologies: Java, Git, RxJava, Kotlin, Android SDK

Software Engineer

2015 - 2016
Node1 (via Software Mansion)
  • Developed and deployed (Heroku) a Node.js middleware service for order management. The goal was to expose a SOAP API serving the data from a MySQL database and XLS files imported from Amazon S3.
Technologies: JavaScript, Git, Unix, Heroku, Amazon S3 (AWS S3), SOAP, Sequelize, MySQL, Node.js

Contract Software Developer

2015 - 2015
Sabre Corporation
  • Worked as a full-stack engineer in a large team on the configurable online booking engine for the airline and travel industry.
  • Developed full-stack features such as layouts using JavaScript, HTML, and CSS with Ajax on the front end and Java 7, Spring, Hibernate, and SOAP on the back end.
  • Supported the Test Automation team in maintaining and repairing test scenarios.
  • Resolved defects.
Technologies: i18n, Java, Git, YUI, JavaScript, CSS, HTML, SOAP, Hibernate, Spring, Java 7

Software Engineer

2014 - 2015
Software Mansion
  • Worked in a small Agile team on a native Android app to help people socialize at local events.
  • Built a native Android app allowing users to do sports together with friends, participate in local sports events, and challenge each other.
Technologies: Git, Unix, Facebook SDK, Robospice, Retrofit, Socket.IO, Google Maps API, Java, Android SDK

Web Developer and Industrial Automation Engineer

2011 - 2014
Termo Automatyka S. C.
  • Designed and rebuilt from scratch the company's website. Added keywords, content, and metadata, which greatly increased its SEO ranking.
  • Built the control system for fuel hose thermoforming machines.
  • Cabled the control cabinets, programmed the PLCs, performed on-site validation tests, wrote documentation, and helped in after-sales service.
Technologies: JavaScript, Electrical Engineering, Ladder Logic, PLC, jQuery, MySQL, PHP, CSS, HTML

Electron and PWA Puzzle Game
The goal was to build a demo app - a puzzle game that could be installed as a desktop application, and also available as a web app (specifically a PWA). The web app was implemented in React and TypeScript. The desktop version is an Electron app that wraps the React app. Also, the web app is a fully-fledged PWA (progressive web app). As a PWA, it is installable and live on the user's home screen, without the need for an app store.

Mobile Boutique App

The app was written in React Native and TypeScript. Our team developed a single codebase out of which we were able to publish several branded apps, with different styles, translated into different languages, and aimed at different markets. The biggest challenge in this project was maintaining the configuration so that the app could easily be published under different brands from one shared codebase.

Highly Customizable eCommerce Platform for Travel Industry

The project was a full-stack web application with React on the front end and Java 8 and Spring on the back end. Our team built an eCommerce platform delivered to enterprise clients and used by consumers that could be customized to the needs of both. Developing only a single codebase, we were able to build applications with different styles and business models. Our team paid particular attention to security, according to the OWASP best practices and standards regarding the development of web applications.

Internal ERP with Elixir and GraphQL

The main goal was to develop a production-quality app with Elixir and Phoenix Framework, serving a GraphQL API on the back end, and React with Relay on the front end. I was able to fully explore the advantages and drawbacks of the Elixir language with Phoenix, Absynthe, and Ecto frameworks. I learned a lot about the GraphQL API - its blessings and curses from both front end and back-end perspectives.

Android App for Home Automation

The app was written in Kotlin, using Dagger2 for dependency injection, RxJava, Retrofit for data fetching, and Google Location and Maps API. The app was communicating with a REST API serving the home automation data from thermostats, e.g., the current temperature, or the currently set temperature according to the schedule. The goal was to demonstrate the possible use case of a home automation app that could monitor and configure the intelligent thermostats in real-time.
2013 - 2014

Master of Science Degree in Computer Science

AGH University of Science and Technology - Cracow, Poland

2008 - 2013

Bachelor of Science Degree in Computer Science

AGH University of Science and Technology - Cracow, Poland


React, Node.js, Redux-Saga, Google Maps API, Socket.IO, Retrofit, Robospice, Facebook SDK, RxJava, YUI, RxJS, jQuery, MobX


Yarn Workspaces, Knex.js, Sequelize, Webpack, Git, WebStorm, IntelliJ IDEA, Expo, Jenkins, Shibboleth, Firebase Analytics, React Apollo


React Native, Redux, Spring 4, Android SDK, Jest, Electron, Spring, CanJS, Material UI, Hibernate, Angular, Phoenix, Relay


JavaScript, TypeScript, CSS, Java 8, GraphQL, HTML, Sass, Kotlin, Java, Java 7, PHP, Elixir


Functional Programming, Object-relational Mapping (ORM), Object-oriented Programming (OOP), Asynchronous Programming, Concurrent Programming, Continuous Integration (CI)


Unix, MacOS, Oracle Database, Heroku, Amazon Web Services (AWS)


Amazon S3 (AWS S3), MySQL, PostgreSQL, MongoDB, Redis


Styled-components, i18n, SOAP, PLC, Ladder Logic, Electrical Engineering, Material Design

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