Visual Studio Experts in Düsseldorf

(Maternity/Parental Leave: July 2023 – Aug 2024)

• Domain: Payment Domain | Client: Telefonica Germany
• Project: General Payment Service

The General Payment Service is responsible for processing of online payments via external payment service provider like Safer pay and PayPal

• Developed Design of Use (DOU) and interface contract documentation, ensuring clarity and compliance across system integrations
• Designed and delivered REST/SOAP web services with Spring Boot and Spring Data JPA, publishing Swagger contracts through WSO2 API Gateway to improve accessibility and governance.
• Spearheaded the on-premises to AWS Cloud migration, re-platforming from Oracle to PostgreSQL on AWS RDS and deploying services on EC2, improving scalability and cost efficiency.
• Containerized microservices using Docker and orchestrated deployments with Kubernetes, streamlining deployment pipelines and improving system reliability.
• Implemented proactive monitoring and logging via AWS CloudWatch and Kibana, ensuring stability and performance during cutover.
• Enhanced collaboration through code reviews and peer reviews, promoting maintainability and clean coding standards.
• Strengthened quality by writing comprehensive JUnit tests and preparing detailed test cases enabling early defect detection
• Delivered automated API testing with Ready API, Postman, and SOAPUI, and conducted performance testing with JMeter, ensuring reliability in high-transaction environments.

• Analysis and remediation of security vulnerabilities in a risk assessment system for energy trading
• System analysis
• Threat modeling
• Decision-making on vulnerability mitigation strategies
• Implementation of vulnerability detection mechanisms
• Security scans
• DevSecOps practices
• Technical environment: Visual Studio Code, JetBrains Suite, MS Threat Modeling Tool, DevSecOps, Git, AWS, DynamoDB, SQL Server, Endur, Snowflake, Orca
• Languages: C#, JavaScript, TypeScript, Python, PowerShell, Bash, Terraform, SQL

• Supporting several agile teams in the new product development of an enterprise CRM and ERP application
• Web frontend development with Angular 17–21 (microfrontends, Domain-Driven Design, MDB-Bootstrap)
• Backend development with C# and .NET 7–10, MongoDB, MassTransit, RabbitMQ, Entity Framework Core, ElasticSearch (microservices, DDD)
• Technical feature design for assigned tasks
• Technical architecture design including forward-looking planning of AI-supported extension options
• Proof-of-concept implementation of AI-supported workflows with n8n and a locally hosted LLM (Ollama)
• Coordination with stakeholders and Product Owners, support with sprint planning

Result: Delivery of production-ready microservices and frontend modules in agile sprint cycles.

Environment: .NET 7–10 · Angular 17–21 · C# · TypeScript · OpenAPI · Microfrontends · DDD · Kubernetes · Docker · Helm · MS SQL Server · PostgreSQL · MongoDB · MassTransit · RabbitMQ · EF Core · ElasticSearch · Kibana · Azure DevOps · KeyCloak · n8n · Ollama

• Operations and rehabilitation
• During this time, development of:
• Websites zentivo-holding.com zyntra3d.com plancodeautomation.com
• Stock trading software
• Automated trading of all financial instruments listed on the stock exchange, with AI integration
• Project management software
• Automated project administration and project management with automated creation of material lists, electrical schematics, PLC programs, HMI programs, AI functions in control technology, project schedules and cost calculations, as well as quotation preparation and cost tracking.
• AI integration
• 3D printing management
• Various methods for creating 3D models from photos, videos or drawings.
• Creation of files suitable for 3D printing, 3D printer management via API.
• AI integration

Tools: Visual Studio, Codex and Cursor, HTML, Java, Python, PHP, C#, Python, SQL, Jason Script.

AI Strategy & Enablement for SMEs Management consulting – SMEs (e.g. marketing boutique, IT & office services)

Concept and delivery of structured AI introduction and strategy workshops for small and medium-sized businesses. Result: Practical AI status assessment, prioritized use case list, and management decision template as the basis for the next steps in the company’s AI development.

Activities

• Needs analysis and individual preparation of the consulting formats
• Facilitation of a structured AI status assessment including vision, mission, and target picture
• Identification and prioritization of relevant AI use cases and action fields
• Creation of management decision templates and roadmaps
• Raising awareness for opportunities, risks, and success factors of AI introduction
• Support for first customers with AI-supported automation scenarios
• Supporting people and teams through the change process of AI introduction (CM)

Methods / Tools / Technologies

Methods:

• AI status assessment & use case analysis
• Workshop moderation / facilitation
• Requirement Management
• Change Management (PROSCI)

Tools:

• Generative AI tools (e.g. ChatGPT, Claude)
• Automation/AI coding tools (e.g. n8n, Claude Code, Visual Studio, Antigravity)

Technologies:

• Prompt engineering
• AI workflow automation

• Development and maintenance of database-driven applications for managing supplier and food contracts, with extensive use of Oracle PL/SQL for complex business logic and data processing
• Optimization of PL/SQL procedures, functions, and triggers to ensure the performance and scalability of Oracle database solutions
• Ensuring compliance with best practices in PL/SQL development and implementing standards for code quality and data integrity
• Close collaboration with backend and frontend teams to ensure smooth integration between the Oracle database, C#-based APIs, and Azure cloud services

• Design and implementation of an OCI-based DWH and ETL system to replace legacy mainframe applications
• Development of a database optimization strategy and planning the rapid conversion of JCL and COBOL routines to PL/SQL with the help of AI
• Development of an Oracle Apex-based app for internal administrative processes in the public sector (office equipment, employee training)
• Implementation of PL/SQL workflows for approval processes and creation of a responsive mobile version with JavaScript and CSS
• Use of Azure DevOps for backlog and documentation, as well as Git for version control
• Development of REST interfaces for CRM systems
• Replacement and reprogramming of Oracle Forms screens with Oracle Apex and upgrading to the latest Apex versions
• Design of a Git branching strategy and conducting code reviews
• Maintenance and further development of an EDI-based data exchange system based on Oracle Advanced Queuing for the public sector in Austria
• Data analysis and creation of charts in the Oracle Apex frontend; installation of standalone ORDS and Apex 23.1
• Agile working according to the Spotify Model; development of complex Apex screens with the support of Oracle JET
• New development and customization of existing PL/SQL packages, workarounds for database version differences and query optimization
• Development of Apex applications for broker pools to manage and optimize Oracle databases in the banking sector, including SSO-based authorization systems with OAuth2 and Keycloak
• Development of extensive Oracle Apex applications for BI and data mining modernization projects, as well as development of manual and automated projection methods in the frontend
• Implementation of data warehousing projects in the banking sector and use of Scrum and Kanban in team-oriented projects

• Redesign of the “Hessian Platform for Migration and Refugees”
• Technologies: C#, .NET 8.0, ASP.NET WebAPI, Blazor
• Architecture principles: Domain Driven Design, Mediator Pattern, Outbox Pattern, IOSP, Clean Code
• Methodologies: SCRUM, coaching, team lead

• Implementation of communication between heating system modules via the SOME/IP interface in C++
• Development of additional software components in C++
• Execution of unit tests and integration tests in the GitLab CI workflow
• Development of desktop publishing functionality
• Tools: C++, Python, Linux, Robot Framework

• Migration of a .NET Core loyalty program for Snipes, used by mobile cash registers in Snipes stores
• Part of the customer’s digitalization strategy in an agile, cross-functional team with a high level of ownership
• Connecting interfaces to third-party systems (e.g. Brandung, CDS)
• Quality assurance through automated tests
• Carrying out developer, unit, and integration tests
• Patterns & methods used: Clean Code, microservice architecture, agile development with SCRUM
• Technologies & tools used: Spring Boot, Java 23, Java Persistence API (JPA), Azure DevOps, Azure Key Vault, Azure PostgreSQL, Docker & Kubernetes, Git, Graylog, Grafana, JUnit, SonarQube, Jira, Confluence, Prometheus, GitLab, GitLab CI/CD, Visual Studio Code

• Project: Migration of large data sets
• Result: ETL route development with AWS Glue and Talend Open Studio

• Implement the BI solution and replace the old BI landscape
• Sub-project lead for Sales Bonus Plan: Extend the existing solution and migrate to Azure
• Sub-project lead for Cognos migration: Expand the existing data warehouse based on MS technologies
• Analyze business requirements and create the technical solution
• Expand the relational DWH database
• Develop the ETL processes (SSIS)
• Develop the multidimensional database (OLAP cubes/SSAS)
• Use of MS SQL Server 2016 (SSMS, SSIS, SSAS, SSRS), MS SQL Server PDW, Oracle, Power BI, Delta Lake, Databricks, Synapse

• Extraction and transformation of relevant data from the SAP system developed for the bank and consolidation into the existing reporting environment
• Integration of the data into the existing BI model (extending the star schema to a galaxy schema) for generating the funding committee report and the business development report
• Ensuring data quality
• Knowledge transfer to department staff (SAP, SQL database, Power Pivot, DAX)

• Software development for microcontrollers and PCs
• Design of architecture and modular structures based on requirements
• Implementation in programming languages (preferably C, C#)
• Documentation in source code (e.g., Doxygen) and additional documents
• Use of version control and backup systems (e.g., SVN, GitLab)
• Developer testing
• Hardware development of microcontroller-based, digital and analog circuits including power electronics
• Circuit concepts (digital and controller circuits, analog, power electronics)
• Calculation of relevant parts
• Compliance with EMC and safety guidelines
• Simulations and component selection
• PCB implementation: layout, manufacturing data, EMC and safety guidelines
• Support of prototype manufacturing and series ramp-up
• Commissioning of prototypes
• Test development: manual and automated tests, test specifications, test stand conception and equipment selection
• Requirements management and maintenance (requirements specification)
• Support of certifications and series introductions