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Maciej Rosiek

Maciej Rosiek

Berlin, Germany
Member since November 28, 2015
Maciej is a full-stack software engineer currently living and working in Berlin. He has successfully created highly distributed systems using Java and JEE platform (Spring, JPA, Hibernate), as well as JavaScript and Node.js platform (Express, Loopback), along with front-ends using JavaScript and AngularJS, React.js, or React Native.
Maciej is now available for hire
  • Java, 9 years
  • Spring, 7 years
  • PostgreSQL, 5 years
  • AngularJS, 2 years
  • React Native, 1 year
  • Amazon Web Services (AWS), 1 year
  • Node.js, 1 year
  • React, 1 year
Berlin, Germany
Preferred Environment
Linux, IntelliJ IDEA, Git
The most amazing...
...application I've created is an event processing bus providing near real-time rule-based product information.
  • Full-stack Software Developer
    2016 - PRESENT
    WeltN24 - Axel Springer
    • Supported development of social features for
    • Designed and created a database and API for the comments system.
    • Architected and developed performant and lightweight UI.
    Technologies: React.js, Scala, Java, MongoDB, AWS
  • Full-stack Developer
    2016 - 2016
    Refined Edge Solutions (
    • Owned the existing back-end created using Node.js and Loopback.
    • Migrated the application to another AWS region.
    • Introduced a continuous delivery pipeline using Docker and Elastic Beanstalk.
    • Optimized performance of database queries.
    • Created a new iOS application using React Native.
    Technologies: Node.js, Loopback, PostgreSQL, React Native, AWS
  • Lead Developer/Tech Lead
    2012 - 2016
    • Managed the back-end development team.
    • Spearheaded the design and architecture of the system.
    • Liaised between programmers and management.
    • Took ownership of product delivery.
    • Mentored junior team members.
    • Recruited developers.
    • Developed a distributed eCommerce back-end system with asynchronous event processing, microservices with AWS and Docker, and REST and SOAP APIs.
    • Created front-ends for internal usage development using AngularJS or React.js (Redux) including E2E testing using Protractor and Selenium running on Node.js.
    • Built a messaging bus appliance using HornetQ with monitoring and metrics.
    • Developed a highly scalable distributed event processing component to aggregate product data using Vertx and Kotlin.
    Technologies: Java, Spring, PostgreSQL, CXF, Solr, Kotlin, Vert.x, Scala, Python, JavaScript, AngularJS, Node.js, React.js, Redux
  • Java EE Developer
    2011 - 2012
    On Demand
    • Developed a back-end system for video streaming (VOD).
    • Created new file storage for multimedia data for HLS (HTTP Live Streaming).
    • Supported the maintenance of a CRM using Ruby On Rails.
    • Conducted functional and integration testing using JUnit.
    • Facilitated performance testing using JMeter.
    • Migrated from JBoss 4.2 to JBoss 5.1.
    Technologies: Java, JBoss, EJB 3, JSF, CXF, JPA, Spring, Hibernate
  • Java Web Developer
    2010 - 2011
    Crystal Brains
    • Developed web applications running on Google App Engine.
    • Created an e-learning platform using Ext JS framework.
    Technologies: Java, JavaScript, ExtJS, Maven, Git
  • Java Web Developer
    2008 - 2011
    InsERT S.A.
    • Developed a web application based on Apache Cocoon Framework.
    • Integrated Hippo CMS with existing document repository to provide a complete solution.
    • Migrated Castor JDO to JPA implementation using Hibernate.
    • Migrated Castor XML to JAXB implementation.
    • Created Axis Soap web services.
    • Created and maintained the application front-end using HTML, CSS, and JavaScript (jQuery).
    Technologies: Java, Tomcat, Spring, Hibernate, Castor, Lucene, Axis, XML, XSLT
  • Java Web Developer
    2007 - 2007
    • Developed web application Oversee to monitor telecommunication nodes.
    • Migrated the application from Java version 1.4 to 5.
    • Created web services to exchange data between front-end and back-end components.
    Technologies: Java, J2EE, JBoss, EJB, Struts, JSP, Servlets, Svn
  • Product Repository (Development)

    Big Data product repository as a core component for storing and manipulating product data of one of the biggest eCommerce fashion retailers in Europe. I was the lead developer responsible for designing the API and architecting the components. It was developed using Java, Spring, CXF and PostgreSQL.

  • Messaging Application (Development)

    An embedded HornetQ package, deployable as web application with monitoring and metrics. I was a main developer, responsible for core development and maintenance. This appliance is used as a main event bus for Zalando because of its reliability and availability. I used HornetQ, Java, and Rest APIs to complete this project.

  • Startup Weekend Fashion & Tech Poznan (Other amazing things)

    I was invited as a mentor to a Fashion & Technology startup competition in Poznan. My role was to help develop business ideas revolving around technology and fashion. I'm proud I could help young entrepreneurs to realize their dream ideas.

  • Languages
    JavaScript, Java, SQL, Kotlin, HTML5, Groovy, HTML, CSS, XSLT, Python, Scala
  • Frameworks
    Spring, Spring MVC, Hibernate, JPA, Vert.x, JUnit, Apache CXF, AngularJS, Spring Boot, Redux, React Native, Grails
  • Tools
    Git, Maven, JMeter, Gradle, Apache Solr
  • Paradigms
    Testing, Unit Testing, Test-driven Development (TDD), Agile Software Development, Functional Programming, Reactive Programming
  • Storage
    PostgreSQL, JSON, NoSQL, Spring Data, DynamoDB, MySQL
  • Libraries/APIs
    Node.js, Lucene, React, Cocoon
  • Platforms
    Amazon Web Services (AWS), Docker, JBoss
  • Other
  • Master's degree in Software Engineering
    2004 - 2009
    Wroclaw University of Technology - Wroclaw/Poland
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