Maciej is available for hire
Hire MaciejMaciej Rosiek
Verified Expert in Engineering
Full-stack Developer
Location
Berlin, Germany
Toptal Member Since
February 1, 2016
Maciej is a full-stack software engineer with more than a decade of experience. He has built highly distributed systems using Jakarta EE with Spring, JPA, and Hibernate; JavaScript and Node.js with Express and Loopback; and front ends using JavaScript, Angular, React, and React Native. Maciej is currently a staff software engineer at Google, and he has a master's degree in software engineering.
Portfolio
Google
Java, Kotlin, GraphQL, TypeScript, Angular, RPC, Google Cloud, Architecture...
Zalando
Java, Kotlin, Spring Boot, PostgreSQL, Apache Kafka, React, Redux, Webpack...
MVPF Technologies GmbH
Kotlin, Spring Boot, PostgreSQL, React, Redux, Webpack, TypeScript, Kubernetes...
Experience
Availability
Part-time
Preferred Environment
Git, IntelliJ IDEA, Linux
The most amazing...
...application I've created is an event-processing bus, providing near real-time, rule-based product information.
Work Experience
Staff Software Engineer
2022 - PRESENT
- Led a Google Cloud engineering team building user interfaces and owning an entire stack of front-end and back-end components.
- Drove software best practices and architectural considerations.
- Collaborated with engineering management to mentor and grow all members of the team.
- Optimized team processes to ensure the team meets commitments and delivers high-quality software.
Technologies: Java, Kotlin, GraphQL, TypeScript, Angular, RPC, Google Cloud, Architecture, Microservices, Databases, SQL, Back-end, Data Structures, Object-oriented Programming (OOP), Linux
Full-stack Developer
2021 - 2021
Zalando
- Developed the back-end and front-end distributed eCommerce web applications.
- Set up asynchronous event processing as microservices with AWS, Docker, K8S, and REST APIs.
- Developed a single-page application for internal use that provided a connection between sellers and suppliers.
Technologies: Java, Kotlin, Spring Boot, PostgreSQL, Apache Kafka, React, Redux, Webpack, TypeScript, APIs, REST, Docker, Kubernetes, Amazon Web Services (AWS), Architecture, Microservices, Databases, SQL, Back-end, Data Structures, Object-oriented Programming (OOP), Linux
Full-stack Developer at HeyCar
2020 - 2020
MVPF Technologies GmbH
- Developed back-end and front-end distributed web applications.
- Created Contentful integration between the front end and Contentful APIs.
- Built the ingestion pipeline for the offers provider using K8S Jobs.
Technologies: Kotlin, Spring Boot, PostgreSQL, React, Redux, Webpack, TypeScript, Kubernetes, Amazon Web Services (AWS), Architecture, Microservices, Databases, SQL, Back-end, Object-oriented Programming (OOP), Linux
Full-stack Software Developer
2016 - 2018
WeltN24 (Acquired by Axel Springer)
- Supported the development of social features for welt.de, the online news platform of Die Welt, translated as The World.
- Designed and created a database and API for the comments system.
- Architected and developed a performant and lightweight UI.
Technologies: Amazon Web Services (AWS), MongoDB, Java, Scala, React, CSS, HTML, Front-end, Web Consulting, GraphQL, Full-stack, TypeScript, PostgreSQL, Test-driven Development (TDD), Go, Object-oriented Design (OOD), Apollo, APIs, REST, REST APIs, Architecture, Microservices, Databases, SQL, Back-end, Data Structures, Object-oriented Programming (OOP), Linux
Full-stack Developer
2016 - 2016
Refined Edge Solutions (via Toptal)
- Owned the existing back end created using Node.js and LoopBack and migrated the application to another AWS region.
- Introduced a continuous delivery pipeline using Docker and Elastic Beanstalk and optimized the performance of database queries.
- Created a new iOS application using React Native and React Redux.
Technologies: Amazon Web Services (AWS), React Native, PostgreSQL, Loopback, Node.js, CSS, HTML, Front-end, Web Consulting, Full-stack, Redux-Saga, React, TypeScript, Test-driven Development (TDD), APIs, REST, REST APIs, Back-end, Linux
Lead Developer and Tech Lead
2012 - 2016
Zalando
- Managed the back-end development team and spearheaded the design and architecture of the system.
- Liaised between programmers and management and took ownership of product delivery.
- Mentored junior team members and 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: Redux, React, Node.js, AngularJS, JavaScript, Python, Scala, Vert.x, Kotlin, Solr, CXF, PostgreSQL, Spring, Java, CSS, HTML, Front-end, Web Consulting, GraphQL, Full-stack, Redux-Saga, TypeScript, Test-driven Development (TDD), Object-oriented Design (OOD), Angular, Material UI, Apollo, Angular Material, APIs, REST, REST APIs, Architecture, Databases, SQL, Back-end, Data Structures, Object-oriented Programming (OOP), MySQL, Linux
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: Hibernate, Spring, JPA, CXF, JSF, EJB 3, JBoss, Java, CSS, HTML, Front-end, Web Consulting, Full-stack, Test-driven Development (TDD), APIs, REST, REST APIs, Architecture, Databases, SQL, Back-end, Data Structures, Object-oriented Programming (OOP), Linux
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: Git, Apache Maven, Ext JS, JavaScript, Java, CSS, HTML, Front-end, Web Consulting, Full-stack, APIs, REST, REST APIs, Architecture, Databases, SQL, Back-end, Object-oriented Programming (OOP)
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: Castor EDC, XSLT, XML, Axis, Apache Lucene, Hibernate, Spring, Apache Tomcat, Java, CSS, HTML, Front-end, Web Consulting, Full-stack, APIs, Architecture, Databases, SQL, Back-end, Object-oriented Programming (OOP), MySQL
Java Web Developer
2007 - 2007
ZPAS-NET
- 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: Subversion (SVN), Servlet, Jakarta Server Pages (JSP), Apache Struts, Enterprise Java Beans (EJB), JBoss, Jakarta EE, Java, CSS, HTML, Front-end, Web Consulting, Full-stack, APIs, Databases, Back-end, Object-oriented Programming (OOP), MySQL
Experience
Product Repository
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
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
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.
Skills
Languages
SQL, Kotlin, Java, JavaScript, CSS, HTML, TypeScript, XSLT, Groovy, HTML5, GraphQL, XML, Python, Scala, Go
Frameworks
JPA, Vert.x, JUnit, Apache CXF, Hibernate, Spring MVC, Spring, AngularJS, Spring Boot, Grails, React Native, Redux, Angular, CXF, JSF, Ext JS, Apache Struts, Jakarta Server Pages (JSP), Loopback, Material UI, Angular Material
Libraries/APIs
React, REST APIs, Apache Lucene, Node.js, Redux-Saga, Axis, Cocoon
Tools
Apache Maven, Git, Apache JMeter, Apache Solr, Gradle, IntelliJ IDEA, Solr, Apache Tomcat, Servlet, Subversion (SVN), Webpack
Paradigms
Agile Software Development, Unit Testing, Test-driven Development (TDD), Testing, REST, Microservices, Object-oriented Programming (OOP), Functional Programming, Reactive Programming, Object-oriented Design (OOD)
Storage
PostgreSQL, JSON, Databases, Spring Data, NoSQL, Amazon DynamoDB, MongoDB, MySQL, Google Cloud
Other
Freelancing, Front-end, Web Consulting, Full-stack, APIs, Architecture, Back-end, Data Structures, Apollo, EJB 3, Enterprise Java Beans (EJB), RPC
Platforms
Linux, Amazon Web Services (AWS), Docker, JBoss, Castor EDC, Jakarta EE, Kubernetes, Apache Kafka
Education
2004 - 2009
Master's Degree in Software Engineering
Wroclaw University of Technology - Wroclaw/Poland
Collaboration That Works
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
1
Share your needs
Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2
Choose your talent
Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3
Start your risk-free talent trial
Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.
Top talent is in high demand.
Start hiring