OpenAPI Experts in Munich

• Recurring problem in my own AI-assisted projects: requirements analysis, use cases, and architecture decisions can be created quickly with AI support, but remain difficult to follow and scattered across Markdown files – knowledge is lost as soon as it is no longer in the context window. arknet turns requirements engineering and architecture knowledge into structured, verifiable data instead of plain text: requirements, use cases, and architecture decisions form a consistently linked knowledge graph, traceable from requirement to architecture decision – queryable by both people and AI agents. Technically based on RDF/OWL and a custom MCP server.

• Result: Working MCP daemon, Docker image published automatically to GHCR, nine hexagonal modules, eleven ADRs (including an Open-Core licensing model). Requirements engineering and Ubiquitous Language hexagons are active. Public as a Community Edition under Apache-2.0 since 07/2026 (github.com/kogn-io/arknet), together with the Claude Code plugin and GHCR image; Open-Core model.

• Label: Java, Maven, RDF, RDF4J, OWL, SPARQL, Model Context Protocol, Spring AI, Docker, GitHub, Git, Claude Code, Obsidian, DDD, Hexagonal Architecture, ArchUnit, JUnit, AssertJ, Interface Development, Software Architecture, Continuous Integration, Knowledge Management

• Build and operate an end-to-end MLOps platform on Azure ML and Kubernetes (Kubeflow) for the automated deployment, monitoring, and scaling of forecasting models (including Temporal Fusion Transformer, Informer, Autoformer).
• Implement CI/CD pipelines in Azure DevOps for the full ML lifecycle – from resource provisioning (Terraform), data transformation (Hugging Face Datasets, Pandas, PyTorch, CUDA cluster) through training and evaluation to model registry and endpoint deployment.
• Integrate MLflow for experiment tracking, model versioning, performance monitoring, and automated registration in the Azure Model Registry.
• Develop and containerize PyTorch training jobs (Azure Notebook, Jupyter Notebooks) for price and time series forecasting (PFC models) with automatic rollout via Azure ML Endpoints and REST/gRPC interfaces, Docker containerization, secured with OAuth 2.0.
• Set up monitoring and alerting mechanisms (Prometheus, MLflow Metrics), log centralization, and cost monitoring.
• Automate infrastructure provisioning and model deployment using Terraform, Helm, and Azure CLI; connect to existing market data systems and event pipelines.
• Migrate existing workloads and databases (IONOS → Azure, MongoDB) with integration into central MLOps workflows and internal networks.
• Extend the platform with LLM-based tools (LangChain, LangServe) to integrate GPT-based analysis modules into existing Spring Boot services for market anomaly detection and automated reports.
• Analyze and architect a software solution to process large volumes of data efficiently (>3000 messages/sec.) (market data store).
• Spring Boot / Java 21 container development with RabbitMQ for distributing stock market data via MongoDB (Kubernetes) with fast storage of data in Redis RMaps, deduplication, forwarding messages to Read Model queues, and building Read Models for UI display in MongoDB.
• Integration of RESTHeart to create a REST API for MongoDB.
• Build an Angular frontend to simplify data queries and master data maintenance.
• Agentic coding with remote and local LLMs (Claude Sonnet, Ollama Qwen) and MCP servers.
• Develop Python scripts for transforming and cleaning incoming stock market data (Pandas, scikit-learn).

Tasks

• Further development of a new ERP system with Blazor
• Generation of e-invoices in the XRechnung and Zugferd formats
• UI/UX design Client-server system
• Windows 11 Technology
• Microsoft .NET 9, Git, Azure DevOps, ASP.NET, MSSQL, Blazor Programming languages
• C#, MVVM Development tools
• Microsoft Visual Studio .NET 2022 Database
• MSSQL Industry
• Other

• Spring Boot Software Engineer
• DevOps Engineer (Kubernetes, Azure DevOps)

Toolstack: Java, Spring Boot, Kubernetes, Helm, GitOps, ArgoCD, Docker, Azure DevOps, CI/CD Pipelines, Git, Postgres

• Overall responsibility for the project lifecycle from scope definition to completion
• Close collaboration with platform teams, IT leaders, and external service providers
• Application of SAFe principles and structured sprint work
• Creation of a migration roadmap with clear milestones
• Monitoring of the lifecycle: onboarding, repository migration, replication of permissions, and system tests
• Visualization of the architecture with PlantUML and Gliffy as well as documentation in Confluence
• Regular status reports and running knowledge transfer sessions

Project: Tax Exemption Order Application

The client has an existing application for creating and maintaining tax exemption orders for end customers; design and implementation of a comparable application for internal employees.

• Design and implementation of microservices and the UI for the business area "tax exemption orders" using Domain Driven Design as well as Spring Boot and Angular.
• Implementation of reactive, non-reactive, and asynchronous APIs (Spring REST, WebFlux, GraphQL).
• Development of the Angular application, including state management using Signals, RxJS Observables, and subscriptions.
• Securing the API and the application using OAuth2, JWT, and OpenID Connect.
• Configuration and setup of CI/CD pipelines with Jenkins.
• Collaboration with cross-functional teams and conducting code reviews.

Environment: Java, Spring Boot, Angular 18 & 19 (standalone, signals), RxJs, Bootstrap CSS, Vitesting, OpenShift, Istio, microservices, Kafka, Dynatrace, Jenkins, GitLab, Graylog, Sonar, Oauth2, OracleDB

• Development of dynamic web components for displaying KPIs, intelligent map applications, and operational process analysis tools
• Angular 18+
• Leaflet, MapLibre
• NestJS, JavaScript, HTML, CSS
• PostgreSQL, GraphQL, RabbitMQ
• Gitea, Jenkins, Docker

• Designed and built from scratch the automation framework using Playwright, Typescript, JavaScript, Gherkin, Cucumber, BDD, Maven, IntelliJ IDEA
• Defined, developed and maintained test plans, test scripts, reports and other QA documentation in Confluence
• Created and maintained test data with SQL Server Management Studio, Toad and Faker.js
• Performed web services and API testing using Swagger Open API, SoapUI, JSON, HTML and XML
• Executed functional, smoke, regression, black box, GUI, cross-browser, UAT and E2E testing using CrossBrowserTesting and Safari Web Inspector
• Integrated and maintained automated scripts within sprints following Kanban, CI/CD, GitHub, Docker, Azure Pipelines, Agile, Scrum, Kafka and Kibana
• Raised and managed defects in Azure DevOps
• Conducted mobile testing with Robot Framework and Appium

• As part of developing this project, various apps were developed for an IBM portal environment based on portlets and Spring Boot services, as well as the setup of a BI platform based on QlikView

• Full-stack development of applications, technical analysis, refinement of requirements with the business department, coordination with the customer, DevOps

• Team size: 8 people

• Technology: Java 11.0, Maven, Git, Spring, Hibernate, JUNIT, Mockito, React, Jira, SQL, Spring Boot, CD/CI Jenkins, Kanban, Rest Api, Oracle

• Environment: Eclipse, IBM Rational Application Developer

• Retained post-acquisition (Wirecard to PagoNxt) as key product leader to drive platform migration and product transformation
• Led discovery-to-launch automation of 20+ multi-step onboarding workflows on a 22-system integration platform, cutting activation time by ~90% and reducing operational costs
• Launched Salesforce-based regulated B2B onboarding portals in UK & Spain, enabling new market entry
• Entrusted to recover a delayed, company-critical program; restructured a 20+ member team and revamped Agile processes, stabilizing execution in 6 weeks
• Coordinated platform migration to PagoNxt infrastructure across 12 teams, shipped 3 weeks early, maintaining a 99.9% uptime SLO
• Conceived a self-serve onboarding app for internal teams, validated MVP, and scaled it into a core system
• Owned the product roadmap and quarterly planning, prioritizing the backlog and making trade-offs to maximize delivery impact
• Improved delivery processes across teams, boosting collaboration, and speeding up throughput by ~30%
• Interviewed and onboarded 8+ PMs and engineers across teams; mentored key hires, improving delivery speed and cross-team execution
• Guided architecture discussions to balance rapid delivery, scalability, and long-term business goals
• Led product discovery workshops, validating hypotheses and driving data-informed feature improvements

• Support in building a modern and secure microservice architecture
• Creation of architecture documentation
• Analysis and definition of interfaces with OpenAPI
• Knowledge transfer on architecture
• Support in frontend architecture
• Implementation of rule sets
• Hands-on work in backend and frontend

• Backend development of the cloud-based microservice
• Frontend development of the microfrontend
• Migration of the cloud backend environment
• Rollout of the distributed high-availability Privacy Data Service
• Technologies: Java, Kotlin, Spring Boot, REST Services, Kubernetes, Microsoft Azure, Cloud Security, OpenAPI, Postman, JavaScript, Vue.js, AngularJS, TypeScript, Micro Frontend, Redis, Kibana, Grafana, CI/CD, GitHub Actions, Jenkins, Helm Charts, Sec-Hub, Black Duck, Docker, Maven, Git, Scrum

• Building the company with a focus on connectivity for IIoT and Industry 4.0, iRPA/process automation, advanced robotics and smart systems, sensors and services
• Project management and software architecture for IoT gateway development (since 2020) with protocol translation, IT/OT convergence and GRC
• Developing RPA bots for automating and monitoring industrial processes with an agent-based AI approach (since 2020)
• Implementing unsupervised clustering and anomaly detection for time series data in big data streaming pipelines (since 2021)
• Introducing a Docker-based release train for OTA updates with DevSecOps and CI/CD (since 2018)

Business context:

• Release 1 – direct banking (consumer loans, vehicle financing)
• Integration with a newly developed VWFS customer frontend (checkout)
• Integration with the Check24 portal
• Release 2 – vehicle financing through VW Group dealers
• Integration with the existing dealer system for document submission
• Adaptation of the document processing workflow in the new core banking system
• Integration with the vehicle documents management system
• Integration with a dealer information system

Tasks and responsibilities

• Integration interface between the project developing the new core system and the systems being integrated
• Coordination of integration scenarios, interface content and their technical implementation
• Specification of business and technical requirements for the relevant interfaces
• Planning and tracking of implementation by service providers/development teams
• Management of testing activities, test execution and defect resolution tracking
• Status reporting to stakeholders and program management

Skills and technologies

• Project management, requirements analysis, test management, testing, reporting, stakeholder management
• VTXRM Accipiens, SmartFIX, Jira, Confluence, HP ALM
• APIs, REST, SOAP, OpenAPI, XML, JSON