Kyu-Wang L.-Software Architect & Lead Software Engineer
Check rate
Experience
Software Architect & Lead Software Engineer
Landesamt für Steuern Niedersachsen
The goal of BIENE is to provide a unified tax collection program for all federal states.
Tax collection involves collecting the taxes that have been assessed. This includes, for example, taking due dates into account, recording incoming and outgoing payments, and initiating reminders or refunds. Limitation periods and payment reminders are also important. BIENE handles all payment transactions with banks and accounting.
Set up the architecture and coordinated the provision of development and test environments at the Hannover site
Installed and configured the environments on Linux servers (Apache Kafka, PostgreSQL)
Interface coordination: coordinated and aligned the connection of software products from other departments and their test data
Migrated the application server, JDK, and Maven project structure
Coordinated environments and managed builds
Implemented external interfaces
Delivered business requirements
Designed and implemented RESTful APIs and OpenAPI specifications
Designed and implemented a microservice architecture
Set up and maintained CI/CD pipelines
Deployed applications on OpenShift
Created technical documentation and diagrams
Worked with SQL databases (Oracle and PostgreSQL)
Set up authentication and authorization for the application and users
Containerized the application (automated deployment through the CI/CD pipeline)
Software Developer
REWE Systems
The application consists of several components, each handling specific requirements for Toom Baumarkt (tBM). tBM sends orders in D0.1B format to SCI (Supply Chain Integration), which forwards them to the JSM system. The first component checks which warehouse the message is for. If the order is for warehouse 110, the message is forwarded to the next component for further processing. The next component pushes the order messages into a message queue. The application retrieves the messages asynchronously, reads the header data and order items, and writes them to a Postgres database. Several endpoints provide information about orders. Communication with other systems takes place via JMS or REST. The application implements order reservation functionality.
Set up and configured the project in GitLab
Configured the CI/CD pipeline in GitLab (DevOps)
Configured automatic deployment to Kubernetes (K8s) using a Helm chart
Implemented the REST application (Spring Boot) and JMS listener
Modeled messages with MagicDraw
Implemented the message flow (process)
Modeled the database structures
Set up and configured the monitoring tool (Grafana)
Configured the realm and OIDC client in Keycloak (OIDC: OAuth 2.0)
Set up users, permissions, and access controls in Keycloak
Connected and secured the application (Spring Boot) with Keycloak via OIDC
Created technical documentation in Confluence
Software Developer
Bundesagentur für Arbeit
Work packages are handled across disciplines using agile methods (Scrum). Project tasks for VERA include developing a new frontend for the system, migrating the application server (WebLogic Server) and JDK, test management, deployment, business enhancements (including changes to legislation), and necessary technical changes.
Implemented the new frontend based on the UI design
Extended the backend logic for REST communication and external interfaces
Migrated Oracle WebLogic Server from 11gR1 to 12cR2
Migrated from Oracle Fusion Middleware to Payara
Migrated from Java Oracle JDK 7 to Oracle JDK 8
Integrated Swagger-Core and Swagger-UI into the REST application
Performed load testing and performance optimization
Systematically created unit tests with JUnit (including deriving test cases)
Created technical user stories and sub-concepts
Analyzed and fixed issues found during system testing
Supported knowledge transfer involving internal BA employees
Regularly reviewed project results with stakeholders
Software Developer
ITZBund
The BSI conducted a penetration test of the GSB product at ITZBund. Critical issues with the GSB software were identified: use of insecurely developed software and outdated libraries. The project goal was to address the issues identified by the BSI regarding the outdated versions of Spring Boot, Spring Security, Gradle, and Gradle plugins:
Spring Boot 2.2.11 to Spring Boot 2.5.1
Spring Security 2.2.4 to Spring Security 5.5.0
Gradle 5.5.1 (Groovy DSL) to Gradle 7.2 (Kotlin DSL), including Gradle plugins
Updated Spring Boot 2.2.11 to Spring Boot 2.5.1
Updated Spring Security 2.2.4 to Spring Security 5.5.0
Updated Gradle 5.5.1 (Groovy DSL) to Gradle 7.2 (Kotlin DSL)
Software Developer
Dataport
The information systems product group develops applications that access registers provided by external partners (e.g. Bundeskriminalamt, Bundesverwaltungsamt, Kraftfahrt-Bundesamt). They comprise 16 web applications that help police officers search for personal data, vehicle data, weapons ownership and permit data, and legal proceedings. All applications implicitly provide web service interfaces for machine-to-machine communication, for example, to connect mobile devices.
Requirements analysis
Implemented new web applications
Implemented configuration and logging
User management
Documentation in Confluence
Supported operations
Fixed bugs (ticket handling)
Quality assurance (automated integration tests and GUI tests)
Presented in meetings
Software Developer
ITZBund
Further development and maintenance of ELStAM: Responsible for the interface to the IdNr process. The nationwide ELStAM data pool contains all data required for the wage tax deduction process. The system includes central business logic for creating, storing, and providing individual ELStAM using several application servers and a database management system. ELStAM are created from data provided by the IdNr process and other tax data.
Implementation of business requirements
Ticket analysis
Bug fixing and code changes
Corrections and data cleanup of historical production data
Refactoring complex applications: carrying out complex restructuring
Experience working with and modeling large volumes of data (bitemporal history)
Software Developer
DKV Euro Service
Development of a company portal as part of the eMobility team. In collaboration with Innogy, commercial fleet operators can charge electric cars across different providers and receive just one central invoice.
Data and database modeling
Development of UI components with Angular 6
Implementation of the HTTP/REST interface with Spring Boot
Software Developer
1&1 Telecommunication SE
Implementation and operation of a mail server proxy and client migration. Provision of an HTTP/REST interface for sending emails using the MBulk interface, and operational IT support.
Requirements analysis and specification
Implementation of the HTTP/REST interface
Client migration
Technical documentation
Quality assurance
Test management: carrying out test plans
Operational support
Software Developer
1&1 Telecommunication SE
Enhancement and development of several REST services with Spring Boot: COMET Core Service and development of a new microservice with a frontend (Vaadin).
Requirements analysis
Implementation of REST interfaces
System maintenance: testing, bug fixing
Preparation of technical and user documentation
Operational support
Software Developer
SHS Viveon AG
Development of a standard product in the Marketing & Sales (MaSS) sector: development, further development, and maintenance of software modules and forward-looking software architectures.
Load testing, performance tuning, and optimization
Documentation (software interfaces) and high-level support
Requirements analysis and specification
Implementation of specifications and automated testing
Integration of the ELK Stack (Elasticsearch, Logstash, Kibana) into the application
Advising projects and bringing together business and technical requirements
Preparation of development and user documentation
Software Developer
GK Software AG
Development of a point-of-sale system (Omni-Channel POS).
Implementation of interfaces via web services and checkout processes
Creation and execution of developer tests
Technical documentation in Confluence
System maintenance: testing, bug fixing
Software Developer
Luftfahrtamt der Bundeswehr
Development of a new military flight operations system and migration from the old system (ZDmF and ZFÜ).
System analysis, evaluation and selection of suitable technologies
Implementation of the external data interface and server components (EJB 3.1, JPA 2.0)
Database modeling and data migration to the new data model
Middleware update and client adaptation
Technical documentation
Software Developer
Luftfahrtamt der Bundeswehr
Maintenance and further development of a military flight operations system (ZDmF and ZFÜ).
Gathering and analysis of user requirements
Further development of existing application modules
System maintenance: testing, bug fixing
Technical documentation
Industry experience
See where this freelancer has spent most of their professional time.
Experienced in Government and Administration, Aerospace and Defense, Retail, Information Technology, Telecommunication, and Energy.
Business area experience
See which departments and functions this freelancer has contributed to most.
Experienced in Information Technology, Quality Assurance, Product Development, Operations, Supply Chain Management, and Marketing.
Summary
I am a qualified graduate in business information systems with over 15 years of experience in software development in the Java environment, and I am also a "Certified Scrum Developer (CSD)".
The strong expertise I have gained through various project assignments, my computer science studies, and my keen interest in new technologies enables me to find practical solutions in project situations.
My expertise covers the following areas of computer science: software development and business intelligence. My focus is on software development and web programming. Through my professional work and studies, I have had the opportunity to gain extensive knowledge. I have broad experience in:
- Software development: Java, JavaEE, Spring (Spring Boot), Hibernate, DB (Oracle, DB2, MySQL), Eclipse-RCP, GUI (Vaadin, Angular, SWT)
- Web programming: HTML, CSS, JavaScript
I have always worked in software development, so I am familiar with the tasks and processes involved in project work.
My personal goal is always to deliver excellent results on time.
Skills
Areas Of Expertise
- Over 15 Years Of Software Development Experience In The Java Environment
- Analytical And Problem-Solving Skills, Quick Learning, Determination
Relevant Experience
- Very Strong, Extensive It Skills
- Many Years Of It Project Experience Across Different Projects And Industries
- Industry Experience In Retail, Telecommunications & Media, And The Public Sector
Industry Knowledge
- Retail
- Telecommunications & Media
- Public Sector
Project Lifecycle
- Business Analysis
- Implementation
- Quality Assurance
- Test Management
- Integration
- Migration
- Requirements Management
- It Operations
- Technical Documentation
- Project Management
Consulting Skills
- Technology Implementation
- Agile Consulting
- Platform Implementation
- Technology Selection
- Platform Selection
- Architecture Assessment
- Architecture Consulting
Methods And Frameworks
- Scrum
- Kanban
- Extreme Programming (Xp)
Business Process Management
- Business Process Modeling
- Workflow Management
- Business Process Analysis (Eepk)
- Itil (V2)
- Business Process Model And Notation (Bpmn)
- Signavio
Technologies And Languages
- Java 5 - 17
- Webservice (Rest, Soap)
- Json
- Xml, Xsd, Wsdl
- Java Ee (Ejb, Jpa, Jms, Ws)
- Uml2
- Pl/Sql
- Sql
- Swt, Vaadin, Swing
- Html, Xhtml 1.1, Css (V1-3)
- Jsf, Jsp
- Xsl (Xslt, Xpath)
- Javascript, Jquery
- Groovy
- Angular 6
- Abap (Sap R/3, Mysap)
- Sas
- C (Ansi C 99)
- C/Al (Microsoft Dynamics Navision)
- Dom, Ajax
Frameworks
- Spring: Spring Boot, Spring Data Jpa, Spring Data Mongodb, Spring Data Rest, Spring Security, Spring Hateoas, Spring Mvc, Spring-Webflow
- Hibernate
- Eclipse-Rcp
- Osgi
- Struts
- Apache Axis2
Databases
- Oracle
- Db2
- Postgresql
- Mysql
- Derby
Servers
- Web Servers: Tomcat, Jetty
- Application Server: Jboss Eap 7.4 (Wildfly)
- Oracle Weblogic
Development Tools And Tools
- Intellij
- Eclipse
- Gitlab
- Git
- Svn
- Cvs
- Ibm Rational Synergy
- Maven
- Gradle
- Ci/Cd Pipeline: Jenkins, Bamboo, Gitlab, Bitbucket, Artifactory, Sonarqube, Pmd, Openshift, Devops
- Mysql Workbench
- Sourcetree
- Jira
- Confluence
- Aqua Data Studio
- Sql Developer
- Dbvisualizer
- Reporting Tool (Birt): Business Intelligence And Reporting Tools
- Hp Quality Center
- Camunda Bpm
Additional Skills
- Elk Stack: Elasticsearch, Logstash, Kibana
- Software Architecture: Microservices, Soa
- Refactoring In Large Software Projects: Carrying Out Complex Restructuring
- Data And Database Modeling
- Oop, Aop
- Design Patterns
- Geographic Information System: Luciad Map
- Data Warehouse: Etl
- Data Quality Management
- Search Engine Optimization (Seo)
- Document Management System: Alfresco
- Content Management System: Pirobase 7
- Erp Systems: Sap R/3-System, Mbs Dynamics Navision
Languages
Education
TH Köln, Campus Gummersbach
Diplom-Wirtschaftsinformatik · Business Information Systems · Gummersbach, Germany
Certifications & licenses
Certified Scrum Developer® (CSD®)
Eclipse E4 RCP Training
Document Management System Training: Alfresco
Statistics
Experience
Global experience
Expertise
Qualifications
Frequently asked questions
Have questions? Find more information here.
Kyu-Wang is based in Lindlar, Germany and can operate in on-site, hybrid, and remote work models.
Kyu-Wang speaks the following languages: German (Native), Korean (Native), English (Intermediate).
Kyu-Wang has at least 15 years of experience. During this time, Kyu-Wang has worked in at least 2 different roles and for 10 different companies. The average length of individual experience is 1 year and 2 months. Note that Kyu-Wang may not have shared all experience and actually has more experience.
Based on recent experience, Kyu-Wang would be well-suited for roles such as: Software Architect & Lead Software Engineer, Software Developer.
Kyu-Wang's most recent position is Software Architect & Lead Software Engineer at Landesamt für Steuern Niedersachsen.
In recent years, Kyu-Wang has worked for Landesamt für Steuern Niedersachsen, REWE Systems, and Bundesagentur für Arbeit.
Kyu-Wang is most experienced in industries like Government and Administration, Aerospace and Defense, and Retail. Kyu-Wang also has some experience in Information Technology, Telecommunication, and Energy.
Kyu-Wang is most experienced in business areas like Information Technology, Quality Assurance, and Product Development. Kyu-Wang also has some experience in Marketing, Operations, and Supply Chain Management.
Kyu-Wang has recently worked in industries like Government and Administration and Retail.
Kyu-Wang has recently worked in business areas like Information Technology, Quality Assurance, and Operations.
Kyu-Wang attended TH Köln, Campus Gummersbach for Business Information Systems.
Kyu-Wang has 3 certificates. These include: Certified Scrum Developer® (CSD®), Eclipse E4 RCP Training, and Document Management System Training: Alfresco.
Kyu-Wang will be available full-time from January 2027.
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Calculated based on our freelancers’ daily rates as of 7 Nov 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
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