Maciej Rosiek - Full Stack Developer

Q: Where is Maciej based?

Maciej is based in Berlin, Germany .

Q: What languages does Maciej speak?

Maciej speaks the following languages: Polish (Native), German (Advanced), English (Advanced) .

Q: How many years of experience does Maciej have?

Maciej has at least 18 years of experience. During this time, Maciej has worked in at least 7 different roles and for 11 different companies . The average length of individual experience is 1 year and 5 months . Note that Maciej may not have shared all experience and actually has more experience.

Q: What is Maciej's latest experience?

Maciej's most recent position is Full Stack Developer (Freelancer) at Runbuggy .

Q: What companies has Maciej worked for in recent years?

In recent years, Maciej has worked for Runbuggy , Wacker , Google , and Zalando .

Q: Which industries is Maciej most experienced in?

Maciej is most experienced in industries like Information Technology , Retail , and Fashion . Maciej also has some experience in Manufacturing , Transportation , and Chemical .

Q: Which business areas is Maciej most experienced in?

Maciej is most experienced in business areas like Information Technology and Product Development .

Q: Which industries has Maciej worked in recently?

Maciej has recently worked in industries like Information Technology , Transportation , and Chemical .

Q: Which business areas has Maciej worked in recently?

Maciej has recently worked in business areas like Information Technology and Product Development .

Recommended expert

Berlin, Germany

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Experience

Feb 2023 - Present

3 years 5 months

Full Stack Developer (Freelancer)

Runbuggy

Led development of RunBot AI assistant autonomously using LLM-powered workflow automation (React, TypeScript, Java, MongoDB, NATS)
Architected TMS platform providing unified transportation management and real-time logistics visibility with AI processing pipelines
Designed event-driven microservices architecture supporting marketplace
Drove architectural decisions and technical leadership across full-stack platform development

Feb 2023 - Present

3 years 5 months

Berlin, Germany

Full Stack Developer (Freelancer)

Wacker

Leading full-stack development of MES and shop floor management platform for large-scale chemical manufacturing facility (C#, MSSQL Server, Kafka, React, Next.js, TypeScript, GraphQL)
Driving architectural decisions and system design across entire solution stack
Leading and mentoring development team members on technical implementation and engineering best practices
Delivering scalable, production-grade software solutions for critical manufacturing operations
Integrating real-time data processing with Kafka to enable seamless shop floor monitoring and control

Jan 2022 - Jan 2023

1 year 1 month

Warsaw, Poland

Staff Software Engineer (Full-Time)

Google

Leading Google Cloud engineering team building user interfaces and owning entire stack of frontend and backend components (TypeScript, Angular, Kotlin)
Driving software best practices and architectural considerations
Working with engineering management to mentor and grow all members of the team
Optimizing team processes to ensure the team is meeting commitments and delivering high-quality software

Jan 2021 - Dec 2021

1 year

Berlin, Germany

Full Stack Developer (Freelancer)

Zalando

Development of distributed ecommerce web applications (backend and frontend)
Asynchronous event processing
SPA for internal usage
Microservices with AWS and Docker, K8S, Rest API
Technologies: Java, Kotlin, Spring Boot, PostgreSQL, Kafka, Nakadi; React, Redux, Webpack, Typescript

Jun 2020 - Dec 2020

7 months

Full Stack Developer (Freelancer)

HeyCar - MVP Factory / BCG DV

Development of distributed web applications (backend and frontend)
Technologies: Kotlin, Spring Boot, PostgreSQL; React, Redux, Webpack, Typescript

May 2019 - May 2020

1 year 1 month

Berlin, Germany

Full Stack Developer (Freelancer)

Zalando

Development of distributed ecommerce web applications (backend and frontend)
Asynchronous event processing
SPA for internal usage
Microservices with AWS and Docker, K8S, Rest API
Technologies: Java, Kotlin, Spring Boot, PostgreSQL, Kafka; React, Redux, Webpack, Typescript

Oct 2018 - May 2019

8 months

Frontend Developer (Freelancer)

QiO Technologies Ltd

Development of frontend applications for 3rd party customer: SPA, Industry 4.0
Integration and development of highly extendable frontend architecture
Technologies: Angular 7, Polymer 2; Typescript, JavaScript, HTML Components

Jan 2017 - Apr 2017

4 months

Full Stack Developer (Freelancer)

Campudus

Development of frontend and backend for Winora (B2B Web Application)
Rest APIs
Performant and lightweight frontend
Mobile First
Technologies: NodeJS, ES6, Typescript, ReactJS, React Native, Redux, Redux Saga, Webpack 2
Development of desktop client for Winora (B2C Kiosk application)
Performant and innovative desktop client
Electron packaged ReactJS application with great emphasis placed on animations and look
Technologies: Electron, Typescript, ReactJS, Redux, Redux Saga, Webpack

May 2016 - Sep 2018

2 years 5 months

Berlin, Germany

Full Stack Developer (Freelancer)

Spring Media (Axel Springer)

Development of frontend and backend social features of welt.de
Database design
Rest/GraphQL APIs
Microservices with AWS and Docker
Performant and lightweight frontend
Mobile First
Technologies: Java, Go, Kotlin, Spring, MongoDB, Gradle; Typescript, React, Webpack; AWS, EC2, CI, Jenkins, Rest API, Microservices, Docker, GraphQL

Apr 2016 - Dec 2016

9 months

Mobile Developer (Freelancer)

Toptal

Development of mobile application clapit.com: Backend - NodeJS, Loopback, PostgreSQL, AWS; Frontend - iOS, React Native, ES6
Development of mobile application knxn.com: Frontend - iOS and Android, React Native ES6/Flow

Jul 2012 - Mar 2016

3 years 9 months

Berlin, Germany

Lead Developer / Tech Lead (Full Time)

Zalando

Management of backend development team: supervision of design and architecture of the system, communication between programmers and management, taking ownership of product delivery, mentoring of junior team members, recruitment of developers
Development of distributed ecommerce backend system: asynchronous event processing, microservices with AWS and Docker, Rest and SOAP API
Technologies: Java, Spring, PostgreSQL, CXF, Solr, Kotlin, Vert.x, Scala, Python

Sep 2011 - Jun 2012

10 months

Wrocław, Poland

Java EE Developer (Full Time)

On Demand

Development of backend system for video streaming (VOD)
High performance, multi user system
Technologies: Java, JBoss, EJB 3, JSF, CXF, JPA, Spring, Hibernate

May 2008 - Aug 2011

3 years 4 months

Wrocław, Poland

Java Web Developer (Full Time)

InsERT S.A.

Development of web application based on Apache Cocoon Framework
Technologies: Java, Tomcat, Spring, Hibernate, Castor, Lucene, Axis, XML, XSLT
Unit and functional testing (TDD)
Little applications written in PHP, Ruby on Rails, Grails

Industry Experience

See where this freelancer has spent most of their professional time.

Experienced in Information Technology, Retail, Fashion, Manufacturing, Transportation, and Chemical.

Information Technology

Retail

Fashion

Manufacturing

Transportation

Chemical

Business Area Experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology and Product Development.

Information Technology

Product Development

Summary

I am a full stack developer with years of experience designing and building scalable solutions across various industries such as ecommerce, manufacturing, and cloud services. I have a strong background in building distributed systems, event-driven microservices, and AI-powered applications. I take pride in my ability to lead technical decisions, mentor teams, and deliver high-quality interfaces and backend components.

I excel in creating unified platforms, real-time data processing systems, and mobile applications with a focus on performance and innovation. My work consistently emphasizes reliability, maintainability, and a clear focus on solving practical challenges.

Skills

Backend Development

Programming Languages: Java, Javascript, Typescript, Go, Kotlin, C#
Main Tools And Libraries: Spring, Maven, Gradle, Aws, Git, Docker, Hibernate, Jpa, Node.Js, Microservices, Rest, Graphql
Databases: Postgresql, Mongodb, Mysql, Dynamodb, Mssql Server, Nats, Kafka

Frontend Development (Web And Mobile)

Programming Languages: Javascript, Typescript, Html, Css
Main Tools And Libraries: React, React Native (Ios And Android), Angular, Rest, Graphql

Other

Vite, Tanstack, Webpack, Babel, Jest, Mocha, Electron

Languages

Polish

Native

German

Advanced

English

Advanced

Education

Sep 2004 - Jul 2009

Wrocław University of Technology

Master degree, Software Engineering · Computer Science · Wrocław, Poland

Statistics

Experience

Total positions 13

Experience in Information Technology 10 y

Avg length 1 y 8 m

Longest experience 3 y 8 m

Global Experience

Countries worked in 2 (Germany, Poland)

Primary country Germany

Expertise

Recent roles Full Stack Developer (Freelancer), Staff Software Engineer (Full-Time), Frontend Developer (Freelancer)

Main industries Information Technology, Retail, Fashion

Main business areas Information Technology, Product Development

Qualifications

Highest degree Master

Profile

Created

June 2026

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Frequently asked questions

Have questions? Find more information here.

Where is Maciej based?

Maciej is based in Berlin, Germany.

What languages does Maciej speak?

Maciej speaks the following languages: Polish (Native), German (Advanced), English (Advanced).

How many years of experience does Maciej have?

Maciej has at least 18 years of experience. During this time, Maciej has worked in at least 7 different roles and for 11 different companies. The average length of individual experience is 1 year and 5 months. Note that Maciej may not have shared all experience and actually has more experience.

What roles would Maciej be best suited for?

Based on recent experience, Maciej would be well-suited for roles such as: Full Stack Developer (Freelancer), Staff Software Engineer (Full-Time), Frontend Developer (Freelancer).

What is Maciej's latest experience?

Maciej's most recent position is Full Stack Developer (Freelancer) at Runbuggy.

What companies has Maciej worked for in recent years?

In recent years, Maciej has worked for Runbuggy, Wacker, Google, and Zalando.

Which industries is Maciej most experienced in?

Maciej is most experienced in industries like Information Technology, Retail, and Fashion. Maciej also has some experience in Manufacturing, Transportation, and Chemical.

Which business areas is Maciej most experienced in?

Maciej is most experienced in business areas like Information Technology and Product Development.

Which industries has Maciej worked in recently?

Maciej has recently worked in industries like Information Technology, Transportation, and Chemical.

Which business areas has Maciej worked in recently?

Maciej has recently worked in business areas like Information Technology and Product Development.

What is Maciej's education?

Maciej holds a Master in Computer Science from Wrocław University of Technology.

What is the availability of Maciej?

Maciej will be available from October 2026.

What is the rate of Maciej?

Maciej's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.