Jan G. - Master Data Application

Q: Where is Jan based?

Jan is based in Düsseldorf, Germany and can operate in on-site , hybrid , and remote work models.

Q: What languages does Jan speak?

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

Q: How many years of experience does Jan have?

Jan has at least 18 years of experience. During this time, Jan has worked in at least 26 different roles and for 13 different companies . The average length of individual experience is 1 year and 8 months . Note that Jan may not have shared all experience and actually has more experience.

Q: What is Jan's latest experience?

Jan's most recent position is Master Data Application at confidential .

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

In recent years, Jan has worked for confidential , welivit GmbH , Kombiverkehr GmbH , and ecotel communications AG .

Q: Which industries is Jan most experienced in?

Jan is most experienced in industries like Information Technology (IT) , Media, Entertainment and Publishing , and Retail . Jan also has some experience in Transportation and Logistics , Manufacturing , and Telecommunication .

Q: Which business areas is Jan most experienced in?

Jan is most experienced in business areas like Information Technology (IT) , Product Development , and Project Management . Jan also has some experience in Customer Service , Finance , and Business Intelligence .

Q: Which industries has Jan worked in recently?

Jan has recently worked in industries like Transportation and Logistics , Information Technology (IT) , and Telecommunication .

Q: Which business areas has Jan worked in recently?

Jan has recently worked in business areas like Information Technology (IT) , Project Management , and Product Development .

Recommended expert

Düsseldorf, Germany

Experience

Feb 2025 - Present

1 year 1 month

Remote

Master Data Application

confidential

Visualization, search, and maintenance of various types of master data, providing them via a REST API, and implementing a variety of import and export formats.
Implementation, architecture, project management.
Technologies and tools: Angular (Signals, Signal Store, swagger-codegen, standalone components), Java, PostgreSQL, ActiveMQ, JavaScript, Spring Boot (Spring Core, Spring MVC, Spring Data/JPA via Hibernate, Spring Security, Spring Modulith), JUnit, Flyway, QueryDSL, GraphQL, REST API, Node, npm, Maven, SonarQube, GitLab CI/CD pipelines, Docker, Nexus, OpenAPI + Swagger UI, Keycloak, OAuth2, OpenID Connect, IntelliJ IDEA, Jira, Confluence.

Oct 2024 - Dec 2024

3 months

Plant Profile Online

welivit GmbH

Management of solar plant data including technical components, photos, and commercial data for contracts, insurance, and orders.
Integration of VCOM monitoring to track outages and manage service providers.
Automatic invoice recognition with assignment to companies, plants, and contracts, review, approval, and payment via the banking system.
Dashboard for an overview of tasks and action status.
Integration of the fund management email inbox to handle incoming emails.
Storage of all documents via REST API in the document management system.
Implementation.
Technologies and tools: Java, Spring, Vaadin (migration from version 7 via 8 to 23 and 24), Hibernate, Camunda BPMN, Quartz, REST, JUnit, Mockito, Selenium, Testbench, MySQL, Tomcat, Maven, GitLab, Jenkins, SonarQube, Nexus, Jira, Confluence.

Apr 2024 - Oct 2024

7 months

Master Data Application

confidential

Visualization, search, and maintenance of various types of master data, providing them via a REST API, and implementing a variety of import and export formats.
Authentication using OAuth2 (OIDC) with Keycloak in the frontend and backend (Spring Security).
Implementation, architecture, project management, team leadership.
Technologies and tools: Angular (Signals, Signal Store, swagger-codegen, standalone components), Java, PostgreSQL, JavaScript, Spring Boot (Spring Core, Spring MVC, Spring Data/JPA via Hibernate, Spring Security, Spring Modulith), JUnit, Flyway, QueryDSL, GraphQL, REST API, Node, npm, Maven, SonarQube, GitLab CI/CD pipelines, Docker, Nexus, OpenAPI + Swagger UI, Keycloak, OAuth2, OpenID Connect, IntelliJ IDEA, Jira, Confluence.

Aug 2021 - Mar 2024

2 years 8 months

CAT

Kombiverkehr GmbH

Analysis of the codebase and refactoring (Spring → Spring Boot, Hibernate 4 → 5).
Optimization of business processes through code reviews and reverse engineering.
Introduction of Apache Kafka (Kafka Streams) as a potential replacement for Camel.
Implementation of new requirements (e.g. refactoring of the schedule importer).
Setup of CI/CD processes with GitLab pipelines, Nexus, Sonar, Ansible.
Creation of observability tools for the OpenIT Cockpit (scripts with Jolokia for JMX metrics).
Improvement of observability using Graylog and introduction of correlation IDs.
Direct access to the Unix shell for configuring systemd jobs.
Improvement of search performance through MongoDB projections.
Evaluation and prototyping for a browser-based replacement of the Eclipse RCP client with Angular.
Implementation with NX for modularization and preparation for a micro-frontend environment.
Replacement of Jasmine with Jest and application of modern Angular concepts (Signals, Signal Store).
Interim team leadership with development planning and stakeholder management.
Project management, team leadership, architecture, implementation, DevOps.
Technologies and tools: Java 8, Java 21, Apache Camel, Spring Boot, Spring Core, Spring Data JPA + JDBC (Informix), Informix DB, stored procedures, MongoDB, Spring WebMVC, Spring Security, Angular, PrimeNG, Jest, JUnit, Swagger, Eclipse RCP, Keycloak, OAuth2, OpenID Connect, ActiveMQ, JMS, REST API, Apache Kafka, Graylog, Node, npm, Maven, Ansible, OpenAPI, IntelliJ IDEA, GitLab CI/CD pipelines, Docker, Nexus, Jira, Confluence.

Aug 2020 - Jun 2021

11 months

NBSS

ecotel communications AG

Creation of BPMN-based business processes based on product management requirements and reverse engineering.
Reimplementation of the inventory system in a microservice architecture with Camunda orchestration.
Integration of external service providers and provision of an API for a separately developed frontend.
Evaluation of microservice tools (e.g. Spring Cloud Config, Spring Boot Admin).
Architecture and implementation.
Technologies and tools: Java 11, Spring Boot (Spring Data/JPA, MVC), MariaDB, Camunda, ActiveMQ, JMS, microservice architecture, OpenAPI, IntelliJ IDEA, GitLab.

Jan 2020 - Feb 2020

2 months

Vacation Management

COMINTO GmbH

Implementation of an internal vacation management system.
Implementation based on Angular (Controller, Services, Forms, Authentication, CLI) with the Clarity UI framework.
Design and development.
Technologies and tools: Angular/Angular CLI, Node.js, npm, IntelliJ IDEA, Jira, Confluence.

Oct 2019 - Dec 2019

3 months

Explain Service

ARD, ZDF, Deutschlandradio Beitragsservice

Tool for receiving SQL queries (DB2) via REST, executing them against DB2, storing the results, and displaying them graphically.
Build integration: Abort if CPU cost thresholds are exceeded, approval via graphical interface.
Design and development.
Technologies and tools: Java 11, Spring Boot, Spring Data JPA (Postgres + DB2), Spring Security (LDAP), Spring Vaadin, Spring Web MVC, Maven, IntelliJ IDEA, Jenkins, Vaadin 14.

Oct 2019 - Dec 2019

3 months

TDET

ARD, ZDF, Deutschlandradio Beitragsservice

Porting a Java SWT application to a browser environment for test data creation.
Graphical interface displays test sets; users can create their own sets and enable start via REST.
Design and development.
Technologies and tools: Java 11, Spring Boot, Spring Data JPA (Postgres + DB2), Spring Security (LDAP), Spring Vaadin, Spring Web MVC, Vue.js, Maven, IntelliJ IDEA, Jenkins.

Feb 2019 - Aug 2019

7 months

Ticket Connector

ecotel communications AG

Wrapper for the OTRS web service to connect various internal and customer systems.
Aggregation of existing systems and dynamic connection to the OTRS backend.
Technologies and tools: Java 11, Spring Boot, Spring Data/JPA (Hibernate), Spring Web MVC, MySQL, SOAP, REST, Swagger, SoapUI, Maven, IntelliJ IDEA, GitLab.

Nov 2018 - Aug 2019

10 months

Quality Report

ecotel communications AG

Aggregation and analysis of existing data with presentation in a web frontend.
Porting a shell script + Perl project to Java/Spring Boot and refactoring the algorithms.
Technologies and tools: Java 11, Spring Boot, Spring Data/JPA (Hibernate), Spring Web MVC/Webflux, Thymeleaf, MySQL, Oracle, Postgres, jQuery Datatables, Bootstrap, Maven, IntelliJ IDEA, GitLab.

Sep 2018 - Jan 2019

5 months

Pandora

ecotel communications AG

Migration of enterprise processes to a microservice architecture.
Integration of external REST interfaces as a facade.
Mapping of external data models into a central manager model (MongoDB).
Technologies and tools: Java 8, Spring Boot, Spring Data/JPA (Hibernate), MySQL, Oracle, MongoDB, REST, jQuery Datatables, ActiveMQ, Maven, IntelliJ IDEA, GitLab, Jax-WS, Apache CXF.

Aug 2018 - Jul 2020

2 years

Online-BKM

Blätterkatalog

Porting the SWT application BKM to a cloud-native solution with a microservice architecture.
Extracting required functions through reverse engineering from the legacy application.
Backend based on event-driven communication with Apache Kafka, REST API using Spring Web.
Frontend implementation with Vue.js.
Implementation.
Technologies and tools: Java 11, Spring Boot, Apache Kafka, Spring Cloud Stream, Spring Batch, Spring Web, JavaScript/Vue.js, IntelliJ IDEA, Jira, Confluence.

Jun 2018 - Jul 2018

2 months

Redesign App-Machine

Blätterkatalog

New development of the App-Machine with current technologies, a modern UI, and features to automate app creation.
Handover, finalization, bug fixes, operation.
Technologies and tools: Java, Spring Boot, Spring Data/JPA, Spring Security, Spring Core, Hibernate, MySQL, Thymeleaf, Kotlin, Jenkins, iOS/Xcode, Android, IntelliJ IDEA, jQuery, Maven, Scrum, Jira, Confluence.

Jan 2017 - Dec 2018

2 years

Newsfeed

Blätterkatalog

Aggregation of various news sources in the Android app.
Project management and development.
Technologies and tools: Java, Android, RxJava, Retrofit, RSS feed, Atom feed, YouTube API, Twitter API, Facebook API, Realm, Scrum, Jira, Confluence.

Jan 2015 - Dec 2018

4 years

Android App (native)

Blätterkatalog

Replacing the cross-platform solution with a native Android app in Java.
Technical project management and development.
Technologies and tools: Java, Android, Realm, RxJava, Retrofit, Kotlin, Docker, Gradle, Scrum, Jira, Confluence.

Jan 2015 - Dec 2018

4 years

Blätterkatalog Modules

Blätterkatalog

PrintSave module: printing/saving PDF page ranges.
Checkout module: cart export and creation of order fax/email.
Recommendation module: interface for sharing content via email and social media.
Global search and Lucene-based search in PHP for full-text search in issue archives.
Project management and development.
Technologies and tools: PHP, Zend Framework, FPDF, Apache, SMTP, MySQL (myISAM full-text index), Scrum, Jira, Confluence.

Jan 2015 - Dec 2018

4 years

Global Search Waltertools

Walter AG

Global search for the client Walter.
Technical project management and development.
Technologies and tools: PHP, PDF, SSH, Zend Framework, MySQL (myISAM full-text index), Apache, JavaScript, Scrum, Jira, Confluence.

Jan 2014 - Dec 2018

5 years

Global Search Schachermayer

Schachermayer-Großhandelsgesellschaft m.b.H.

Developed a global search in PHP with a Spring frontend for full-text search across publications.
Developed automated import and update mechanisms.
Technical and business project management and development.
Technologies and tools: PHP, PDF, SSH, Zend Framework, MySQL (myISAM full-text index), Apache, Spring Security, JavaScript, Scrum, Jira, Confluence.

Jan 2014 - Dec 2017

4 years

FileProxy E.R. Ship

E.R. Schiffahrt GmbH & Cie. KG

Secured user data by setting up a file proxy with access restrictions for authorized requests.
Technical and business project management and development.
Technologies and tools: PHP, Scrum, Jira, Confluence.

Mar 2013 - Jun 2014

1 year 4 months

App-Machine

Blätterkatalog

Designed, developed, and built a web application for creating and managing iOS and Android apps with templates for clients.
Maintenance and further development.
Technologies and tools: Java, Spring MVC, Spring Security, Spring Core, Hibernate, MySQL, JSP, Jenkins, iOS/Xcode, Android, Ant, jQuery, Scrum, Jira, Confluence.

Jan 2011 - Dec 2018

8 years

Shelf Manager

Blätterkatalog

Application to generate XML files for controlling mobile app content and sending push notifications via GCM and APN.
Conceptualization, later project management and development.
Technologies and tools: PHP, Zend Framework, GCM, APN, XML, Apache, Caching, jQuery, Scrum, Jira, Confluence.

Jan 2011 - Dec 2016

6 years

Android App (Cross-Platform)

Blätterkatalog

Developed an application initially for web, Android, and Windows (later only Android and Windows) with HaXe.
Project management and development.
Technologies and tools: Java, Android, HaXe, C (SDL), Scrum, Jira, Confluence.

Jan 2010 - Dec 2015

6 years

PDF Text Extraction

Blätterkatalog

Text extraction with coordinates and meta-information from PDF files.
Further development, later project management.
Technologies and tools: C#, Atala, Scrum.

Jan 2009 - Dec 2010

2 years

rescueTec Online Shop

rescue-tec GmbH & Co. KG

Shop system based on xtCommerce.
Further development and bug fixes.
Technologies and tools: PHP, MySQL (myISAM).

Oct 2008 - Jun 2014

5 years 9 months

Flip Catalog Flash

Blätterkatalog

Product 'Flip Catalog' as a Flash application for displaying page-flippable PDF content in the browser.
Further development of the core (ActionScript), frontend development (XML, HTML, Flash), customer support.
Technologies and tools: XML, ActionScript 2/3, HTML.

Mar 2008 - Feb 2010

2 years

Online Shop

UDO BÄR GmbH & Co. KG

Shop applications for the full product range and sub-operators.
Ongoing development and coordination with the client, as well as development of new features.
Technologies and tools: PHP, JavaScript, JShop, Flash, HTML.

Feb 2008 - Apr 2008

3 months

ERGO Access Application

ERGO Versicherungsgruppe AG

Analysis and visualization of an existing Access application (module dependencies and interfaces).
Development and visualization using Access and PDF.

Industries Experience

See where this freelancer has spent most of their professional time. Longer bars indicate deeper hands-on experience, while shorter ones reflect targeted or project-based work.

Experienced in Information Technology (13.5 years), Media and Entertainment (8 years), Retail (7.5 years), Transportation (6.5 years), Manufacturing (4 years), and Telecommunication (2 years).

Information Technology

Media and Entertainment

Retail

Transportation

Manufacturing

Telecommunication

Business Areas Experience

The graph below provides a cumulative view of the freelancer's experience across multiple business areas, calculated from completed and active engagements. It highlights the areas where the freelancer has most frequently contributed to planning, execution, and delivery of business outcomes.

Experienced in Information Technology (17.5 years), Product Development (13.5 years), Project Management (13 years), and Customer Service (5.5 years).

Information Technology

Product Development

Project Management

Customer Service

Summary

Jan is a strong communicator and a senior developer who stands out because he is interested in the project as a whole and not just in his own area. He doesn’t stop at "works for me", but is only satisfied when the entire project is successfully completed.

Skills

Technologies (Cloud)

Apache Kafka +++ Message Bus (Pub/sub), Streams (Pdf Processing)
Platform (Gcp) ++ Gke (Deploying Containers In Kubernetes), Storage
Docker +++ Custom Containers, Orchestration With Docker-compose, Podman
Kubernetes ++ Creating Services (Nodeport, Clusterip) And Deployments Via .Yml Configuration, Distribution With Gke
Keycloak ++ Design, Installation, Configuration, Administration, Oauth2, Openid Connect

Technologies (Backend)

Java +++ Spring Framework (Core, Mvc, Data, Security, Modulith, Webflux), Spring Boot, Reactor, Jpa (Hibernate), Jms, Swagger, Openapi, Apache Camel, Jasperreports, Jax-ws/rs, Apache Cxf, Mapstruct, Flyway
Php +++ Php 4–php 7 (Zend Framework)
Db (Mariadb, Mysql) +++ Myisam, Innodb
Db (Ibm Informix) +++ Tables, Stored Procedures, Views, Triggers
Db (Redis, Etcd) ++ Persistence, Distributed Data
Db (General) ++ Postgres, Oracle, Db2, Mongodb, Sqlite, Realm
Camunda ++ Bpmn

Technologies (Frontend)

Java +++ Swt, Vaadin
Javascript / Typescript +++ Jquery, Vue.js, Angular, Primeng, Jest
Css / Ui ++ Bootstrap.css, Angular, Clarity, Vue.js, Vuetify / Quasar
Html +++ Xhtml, Html5, Thymeleaf (Via Spring Boot)
Php +++ Smarty Template Engine
Android ++ Kotlin, Rxkotlin, Rxjava, Realm, Retrofit, Dagger, Android Jetpack, Material-components-android, Proguard, Okhttp

Programming Languages

Java +++
Haxe +++ Cross-platform App Development
Go +
C / C++ +
C# ++ Atala
Kotlin ++ Android, Core, Spring Boot

Concepts

Event-driven Architecture +++ Apache Kafka, Activemq, Otto Bus (Android Messaging)
Microservices ++ Spring Cloud Config, Spring, Rest
Testing / Test-driven ++ Junit, Mockito, @Springboottest, Postman
Code Quality +++ Sonarqube, Owasp, Gitlab (Code Review), Clean Code
Ci/cd +++ Gitlab, Jenkins, Nexus
Container +++ Docker, Docker-compose
Agile / Scrum +++ 4+ Years In A Scrum Team
Devops ++ Bash, Ansible, Graylog, Jolokia, Jmx, Systemd

Build Tools

Maven +++ Sonatype Nexus As Repository
Ant ++
Gradle ++

Software

Ide +++ Intellij Idea, Datagrip, Phpstorm, Vscode, Eclipse
Scm ++ Cvs, Svn, Git / Gitlab
Bugtracking +++ Jira, Bugzilla, Otrs
Repository Management ++ Nexus

Web Servers

Apache Administration ++
Php (Apache Module, Fcgi, Fpm) +++
Application Server ++ Tomcat, Undertow, Jetty, Netty

Operating Systems

Windows ++ 3.11, 95, 98, 2000, Xp, Windows 7, Windows 10
Linux / Unix ++ Suse, Debian, Centos, Ubuntu

Miscellaneous

Pdf Tools ++ Atala (C# Project), Fpdf (Php), Pdfbox (Java)
Ms Office +++
Confluence ++

Languages

German

Native

English

Advanced

Education

Apprenticeship · IT Specialist in Application Development

Profile

Created

February 2026

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Frequently asked questions

Do you have questions? Here you can find further information.

Where is Jan based?

Jan is based in Düsseldorf, Germany and can operate in on-site, hybrid, and remote work models.

What languages does Jan speak?

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

How many years of experience does Jan have?

Jan has at least 18 years of experience. During this time, Jan has worked in at least 26 different roles and for 13 different companies. The average length of individual experience is 1 year and 8 months. Note that Jan may not have shared all experience and actually has more experience.

What roles would Jan be best suited for?

Based on recent experience, Jan would be well-suited for roles such as: Master Data Application, Plant Profile Online, CAT.

What is Jan's latest experience?

Jan's most recent position is Master Data Application at confidential.

What companies has Jan worked for in recent years?

In recent years, Jan has worked for confidential, welivit GmbH, Kombiverkehr GmbH, and ecotel communications AG.

Which industries is Jan most experienced in?

Jan is most experienced in industries like Information Technology (IT), Media, Entertainment and Publishing, and Retail. Jan also has some experience in Transportation and Logistics, Manufacturing, and Telecommunication.

Which business areas is Jan most experienced in?

Jan is most experienced in business areas like Information Technology (IT), Product Development, and Project Management. Jan also has some experience in Customer Service, Finance, and Business Intelligence.