Agata Andrzejewska, Software Developer in Copenhagen, Denmark
Agata Andrzejewska

Software Developer in Copenhagen, Denmark

Member since September 6, 2017
Agata is a full-stack web app developer with an academic background in computer science and a great interest in algorithms and mathematics. She is passionate about learning and enjoys challenges. She has successfully worked on multiple projects, from designing apps from scratch, implementing secure solutions, and improving app performance to taking care of the best UX and writing clear testable code.
Agata is now available for hire




Copenhagen, Denmark



Preferred Environment

Sublime Text, Git, Linux, MacOS

The most amazing...

...project I was involved in used mathematical statistics, cryptography, and network protocols to send encrypted steganography messages during a VoIP call.


  • Full-stack Developer

    2018 - PRESENT (Open-source Volounteering)
    • Migrated an app from AngularJS to React (in progress).
    • Adjusted the look of the app using Bootstrap.
    • Reviewed code and supported other contributors.
    Technologies: AngularJS, Express.js, Node.js, Bootstrap, React
  • Senior Full-stack Developer

    2019 - 2020
    Client (via Toptal)
    • Rebuilt and improved an existing app from MVP to a secure version with fully developed planned functionalities.
    • Planned and executed all of the processes needed to launch and maintain the app.
    • Designed and implemented the application's front-end architecture with React, Redux, and JavaScript.
    • Designed and implemented the application's back-end architecture with hapi.js and PostgreSQL database.
    • Designed and built a hierarchical comment system for a social app with a focus on performance and good UX.
    • Added tests on the back end, reaching 80% coverage.
    • Fixed security issues on the back end and front end.
    Technologies: React, Node.js, Hapi.js, PostgreSQL, AWS, Docker, SCSS
  • Co-founder | Developer

    2017 - 2019
    • Designed and built parts for additional functionalities in a REST API using Express.js and Node.js.
    • Refactorized part of the validating process on the Node.js/Express.js query path by implementing a parser used as one of the pieces of the middleware software.
    • Designed and implemented REST API responses for various queries using Node.js and ArangoDB Query Language.
    • Added JWT validation to increase the security of the users.
    Technologies: JavaScript, ArangoDB, Angular, Express.js, Node.js
  • Full-stack Developer

    2017 - 2018
    Client (via Toptal)
    • Designed and built multiple REST API microservices using Express.js and Node.js.
    • Engineered and added JWT validation and fixed bugs with security.
    • Pioneered and wrote SQL queries generator for MySQL database.
    • Created detailed tests following the practice of Behavior-driven Development (BDD) covering 95% of the code.
    • Architected and built pages of the front-end app in jQuery.
    Technologies: Docker, Bootstrap, jQuery, MySQL, Express.js, Node.js, Microservices, REST, RESTful APIs
  • Software Developer

    2013 - 2014
    • Modernized the JavaScript code of the front-end by dividing into libraries which increased its simplicity and readability.
    • Created a reusable module using Java for generating PDF documents based on data from a database and HTML forms and integrated it with an existing product.
    • Built new pieces of the application from top to bottom using Java, JavaScript, HTML, CSS, and SQL.
    • Fixed bugs and adjusted the back-end and front-end of the product for the needs of clients.
    Technologies: Java, JavaScript
  • Web Developer

    2007 - 2014
    Independent Work
    • Built full websites using Python Django.
    • Designed relational databases for the use with websites.
    • Developed software using RESTful APIs with Node.js and Express.js.
    • Designed and implemented fully functional websites from top to bottom.
    • Worked with clients on planning and designing products.
    Technologies: SQL, CSS, HTML, Django, Python


  • Ditup

    Here, I developed an internet platform for finding people with similar interests and problems to collaborate.

    Ditup provides a place where people with similar interests, problems, or needs can meet and connect.

    Work Done:
    • Refactorized part of the validating process on the Node.js/Express.js query path by implementing a parser used as one of the pieces of middleware software.
    • Designed and implemented REST API responses for various queries using Node.js and Arango Query Language.
    • Designed and wrote tests for every implemented functionality following BDD standards.
    • Used the JSON schema and JSON web token libraries to increase the security of the website.

  • Influenced

    This is an open-source web app that visualizes how well-known people influenced each other. Based on linked data from

    I developed this in collaboration with Michal Salajka. See more about him at the link below.

    The app runs at the link below.

    Technologies: React, Redux, D3.js, SPARQL

  • Lisbon Nomadbase

    A project exploring the ways to connect people who want to cooperate with each other.

    Work Done:
    • Co-founded and co-created the place.
    • Managed and organized the space.
    • Designed, developed, and maintained the website using Python Django.

  • Dictionary and Book Translator

    An application which helps to read books in foreign languages by quickly translating words and creating dictionaries for a particular book.

    It's focused on a simple and quick performance.
    I researched, designed and implemented the whole project including, searching algorithm and graph database storage of data.

    Technologies: Python, ArangoDB

  • Steganography-based Communicator Based on Different Types of Encryption

    Based on steganography methods and cryptography algorithms, this communicator sends hard-to-detect-by-third-party messages and images through an HTTP protocol.

    Technologies: C++, Java


  • Languages

    JavaScript, SQL, CSS, HTML, Python, SCSS, C, Java, Less, TypeScript
  • Frameworks

    Express.js, JSON Web Tokens (JWT), Bootstrap, Redux, Hapi.js, Angular, AngularJS, Django
  • Libraries/APIs

    Node.js, React, REST APIs, jQuery
  • Other

    Data Structures, Algorithms, RESTful APIs, AWS
  • Tools

    Adobe Photoshop, Git, Sublime Text, GitHub
  • Paradigms

    REST, Pair Programming, Object-oriented Programming (OOP), Test-driven Development (TDD), Behavior-driven Development (BDD), Design Patterns, Testing, Unit Testing, Microservices
  • Platforms

    MacOS, Firebase, Linux, Docker, Windows
  • Storage

    ArangoDB, JSON/XML Schemas, NoSQL, Relational Databases, MySQL, PostgreSQL


  • Completed Credits towards a Bachelor’s Degree in Computer Science
    2009 - 2014
    Warsaw University of Technology - Warsaw, Poland

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