MySQL Experts in Düsseldorf

Project: Introduction of statutory-compliant electronic invoicing (outbound, Germany) in SAP for an international technology group.

• Project management: Planning, steering and reporting of the E-Invoicing outbound rollout across all affected business areas, including budget and resource coordination.
• UAT: Structured user acceptance test with key users per business area, test cases per invoice scenario, and consolidated test results for decision making.
• Defect management: Handover and tracking of defects in Jira, including validation of the generated invoices against the statutory schemas.
• Cutover, go-live and hypercare: Readiness checks and cutover planning aligned with the statutory deadlines, coordination of go-live and stabilization during hypercare.
• Stakeholder management and reporting: Alignment with Finance, Tax, business departments and IT, preparation of status reports and decision papers, and consistent follow-up of open items.
• Change management and documentation: Communicated process changes to the business departments, enabled key users, and created process and compliance documentation to ensure traceability and audit readiness.

• QA Lead for end-to-end quality assurance of the Sparkasse & Sparkasse Business banking apps (iOS/Android); design and implementation of the Test Strategy including functional testing, regression testing, and UAT for eID, Push Notifications, and white-label components
• Creation and maintenance of test concepts and test plans in TestRail; structured Defect Management and error analysis; stakeholder management and risk management for the early identification of critical quality risks
• Accessibility Testing according to WCAG 2.1 (iOS/Android); coordination of AI-supported test automation and optimization of test processes to shorten release cycles
• Release Management: planning, management, and coordination of all test activities; status reporting to management and stakeholders; quality assessment of releases and release recommendations in an Agile/Scrum environment
• Challenge: Highly complex build and release process across several Sparkasse institutions; close coordination with the DevOps team to stabilize the CI/CD pipeline and ensure reproducible test builds before every release.

Tools: Jira, Confluence, TestRail, Android Studio, Xcode, Firebase, Jenkins, GA4

• Success: Successful launch of the eID authentication process - quality assurance ensured for 50+ Sparkasse institutions

• Created data pipelines and visualization tools to support sustainable energy decision-making
• Developed insights that could optimize renewable energy deployment and grid integration strategies

Successful delivery of projects on behalf of customers:

• -> 2023 – present: Project management for the consolidation of sites/data centers for a large telecommunications provider (infrastructure project, customer: Telefonica)

• Opening and preparing new sites

• Application migrations

• Decommissioning and handover of old sites

• -> 2021 – 2022: IT multi-project management for a large car leasing company (customer: Athlon)

• Migration of applications to the cloud and to another data center

• Additional projects to expand and optimize the application landscape

• -> 2021: Project management for the development of a platform providing internet access on aircraft operated by various airlines (customer: m3Connect/German Telekom)

• -> 2017-2020: Responsible management of an IP network consolidation (infrastructure project, customer: Cisco/Vodafone) at a large telecommunications provider

• Planning and coordination of migrations and their rollout

• Team leadership and integration of different teams (network operators, hardware and service providers)

Gronic Ident & Sign

Core technologies: Android, Jetpack Compose, Retrofit, Regula Document Reader, Adobe Sign

Android app on dedicated devices for identifications and electronic signatures at the PoS

• Training AI models, evaluating images and text UI/UX, turning the provided data into insights through OpenAI Feather as part of the machine learning workflow

Technologies: OpenAI Feather

(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.

• Determining the current status (planning status / expansion status) of the so-called interpolygon routes
• Preparing an end-to-end project plan for the individual routes, taking active and passive components and activities into account
• Monitoring and controlling plan implementation
• Optimizing the selected network architecture
• Creating network and splice plans

• 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

• Contributed to the development of an advanced RAG AI Chat application that integrates multiple LLM models, enabling users to seamlessly switch between models based on specific tasks. This improved the user experience by providing tailored, efficient solutions for various use cases, such as event scheduling, booking systems, and complex task management.
• Participated in designing and implementing a robust backend architecture using Spring AI, enabling advanced AI-driven capabilities like intelligent task automation, language processing, and contextual recommendations. Leveraged Spring AI Tools and Advisors to enhance the performance and decision-making of the AI models.
• Collaborated on the integration of vector databases to support embeddings, enhancing the app's ability to understand user queries and perform actions based on complex, real-time data inputs.
• Contributed to the development of a seamless, user-friendly front-end interface using React with TypeScript support, ensuring a modern, responsive, and scalable user experience across platforms.
• Assisted in implementing state management with Redux RTK for efficient data flow and real-time updates, optimizing the overall user experience in dynamic scenarios such as scheduling and task management.
• Partnered with stakeholders to define feature requirements, helping ensure that the app could scale to meet evolving business needs and integrate with other systems like calendar and email services. Worked alongside cross-functional teams, including data scientists and UI/UX designers, to fine-tune AI models and ensure alignment with project goals.
• Contributed to ensuring end-to-end system performance, security, and compliance by helping integrate authentication mechanisms, role-based access control, and secure communication protocols in both backend and frontend layers.

Technology Stack and Key Contributions:

• Java / Spring Boot / Spring AI: Developed backend services leveraging Spring AI for intelligent responses, task automation, and complex workflows.
• React / TypeScript: Built intuitive user interfaces with React and TypeScript, ensuring a smooth and scalable frontend.
• Redux RTK: Managed application state with Redux RTK for optimized state management, enabling dynamic, real-time data updates.
• Vector Databases: Integrated vector databases (pgVector) for embedding support, improving AI model performance in handling complex queries.
• PostgreSQL / Redis: Managed persistent and temporary data with relational and in-memory data stores, ensuring data integrity and speed.
• Kafka: Utilized Apache Kafka for event-driven communication and seamless integration between microservices.
• Spring Security: Ensured the security of backend services with robust authentication and authorization mechanisms.
• CI/CD & DevOps: Integrated continuous integration and deployment pipelines to ensure rapid and secure deployment of features and updates.

• Self-employed PLC and software specialist focusing on automation and special-purpose machinery
• Programming, modernization, expansion and optimization of production systems, focusing on increased efficiency, data transparency and system integration
• PLC programming and safety with Siemens S7 Classic/TIA Portal, Beckhoff TwinCAT 2/3 and CoDeSys
• Development of high-level language software and database applications (.NET / C#, C++, Visual Basic .NET, Borland/Embarcadero C++)
• Development of custom software solutions for industrial automation, including embedded systems (Raspberry Pi, Arduino, NodeMCU, ESP8266)
• Integration of external systems such as reading devices, printers, scales, scanners and cameras, as well as various bus systems (Ethernet, Profinet, Profibus, EtherCAT, CAN bus, RS232, TCP/IP)
• Creation of visualizations and HMI applications with Siemens WinCC flexible, Beckhoff HMI and .NET frontends
• Planning, development and integration of machine vision solutions (Keyence, Cognex, AVS Alfavision, camera systems) in PLC and PC environments
• Design and implementation of process data collection systems and traceability solutions (100% traceability) based on Microsoft SQL Server (Compact, Express, Server), including stored procedures and direct PLC-SQL communication
• Creation of software and PLC concepts, standard function blocks and project libraries for PLC and high-level language projects
• Planning and programming of conveyor, inspection, assembly, packaging and grinding systems in industries such as automotive, chemical, food, electronics, machinery and systems engineering
• Conducting workshops and training on Siemens TIA Portal, STEP7 Classic, Beckhoff TwinCAT (including TwinSAFE), as well as topics such as architectures, safety, database integration and documentation
• Creation of technical documentation, manuals, training materials and class documentation with Microsoft Office and Doxygen
• Project management tasks from requirements analysis through planning, concept development and supplier coordination to commissioning, production support and customer support

• Third-side integration development (REST: Amazon, OpenAI, Etsy, Shopware, Prestashop, etc)

• Performance optimization (Refactoring, SQL analysis)

• LMS development and deployment (Moodle)

• Cloud deployment automation (Amazon, Azure, Gitlab CI/CD, Docker)

• Backend and Frontend development (Laravel, VueJs)

• Collaboration with partner-developers (national and international)

• Shirtigo GmbH

• GRELLARTIG Digital GmbH

• velpTEC edutainment GmbH

• Design and implementation of a system for controlling the complete process of installing, removing, and replacing electricity meters by external service providers for an energy supplier

• Automated retrieval of orders and available devices through defined interfaces (e.g. from SAP)

• Orchestration of the process steps (assignment of meters, processing of meter data, transfer of updated information back to the source system) through a Spring-Boot backend

• Provision of a React-based web client for operational tracking and control of orders, e.g. to continue failed process steps or resend notifications