REST API Experts in Frankfurt

I am an experienced data engineer specializing in end‑to‑end data integration, cloud DWH architectures, and high‑quality, governed data products.

I delivered following projects and engagements as a freelancer.

• Data Migration of CRM System for AL-FA Objekt Service Gmbh
• Microsoft Software Resales Partnership

I am looking for freelance roles like: Freelance Data Engineer Cloud Data Warehouse Architect Data Modeling & Architecture Consultant MDM & Data Governance Specialist BI & Analytics Developer

Technical Focus Areas

• Data Engineering & Integration: SQL Server/SSIS, Informatica PowerCenter/IDQ, Talend, Kafka, Azure Data Factory – Delta/CDC/ELT patterns, robust pipelines, monitoring/recovery, data lineage & impact analysis, medallion architecture Bronze/Silver/Gold layers
• DWH & Cloud: Azure SQL / Data Lake / Synapse, AWS Redshift/S3, on‑prem SQL/Oracle – scalable data marts with a strong cost/benefit focus.
• Data Modeling: Atomic (Inmon) and Dimensional (Kimball), Data Vault (Linstedt), Domain‑Driven Design, clear lineage & contracts.
• MDM & Governance: Informatica MDM, IBM MDM, stewardship processes, data quality rules, survivorship/XREF, catalog/glossary, SIF/BES/REST publication.
• Analytics/BI: Power BI, SSAS, Cognos – business‑ready, maintainable data products.

• Conceptual design and implementation of modular AI assistants for sales and business processes in the Microsoft ecosystem (Agentic AI, Copilot extensions)
• Frontend architecture and development with React + TypeScript for embedded chat and assistant surfaces (streaming UI, hooks, React Query, OpenAPI clients)
• Enterprise-level agent development: reusable skill/agent library, MCP server, review and compliance gates
• LLM integration into the user experience: Anthropic (Claude), OpenAI, tool use, RAG pipelines, prompt engineering, guardrails
• Architecture and code review consulting as well as mentoring in the AI development team
• Integration with Microsoft Graph, Power Platform, and Azure services
• Technologies: React, TypeScript, Anthropic Claude, OpenAI, MCP, RAG, Microsoft Graph, Power Platform, Azure

• Holistic responsibility for modernizing and expanding federal networks and upgrading critical data center and telecom infrastructure in the high-security agency environment of BDBOS
• Planning and management of the expansion of national BOS network infrastructure in the VS-NfD/KRITIS environment with technical decision authority at the architecture and component level (Cisco, Layer 2/3, WAN redundancy)
• Planning, tendering (EVB-IT/UVgO) and oversight of the upgrade of security-critical telecom infrastructure for emergency call 110/112 (ACD)
• Capacity planning, rack integration, structured cabling, power supply, cooling concept (CRAC/In-Row) and DCIM monitoring for data center expansion
• Building the IT department from scratch: structures, governance, processes, team recruiting, vendor selection and long-term IT strategy
• Planning and managing infrastructure and application migrations: migration strategies, batch planning, hypercare stabilization and rollback concepts
• Creating vendor-neutral specifications (telecom systems, signature solutions) according to EVB-IT and UVgO; contract award and vendor management
• Setting up a secure IT environment according to BSI basic protection, ISO 27001 and VS-NfD; developing IT security concepts and CMDB analyses
• Hands-on program leadership: decision papers for management and steering committees, risk management, reporting and change request control

• Porsche ID is a unified digital identity platform providing secure authentication and seamless access across Porsche’s online services, mobile apps, and connected vehicle features
• Designed and implemented new authentication and authorization functionalities for both users and systems
• Ensured high availability, security, and performance to deliver a flawless digital experience for Porsche customers
• Technologies: Auth0, Angular, Tailwind, AWS, Terraform, Github
• Methodologies: Scrum and SAFe

• Analysis of the existing reporting platform including processes and governance topics with stakeholders from sales and marketing.

• Detailed analysis and evaluation of client-defined requirements for existing reporting and new dashboards.

• Supporting stakeholders in managing sales processes and early detection of KPI trends.

• Use of Microsoft Power BI as central analysis and reporting platform.

• Developing a proposal for the necessary evolution of processes and the Power BI platform.

• Gathering current business processes and defining company-wide KPIs in coordination with stakeholders.

• Analysis and inventory of the client's Power BI platform.

• Analysis of processes and data governance.

• Recording and documenting current business processes.

• Developing recommendations for process and reporting platform improvements.

• Designing and implementing dashboards in Power BI.

• Defining company-wide KPIs and aligning them with stakeholders.

• Microsoft Power BI.

• Data analytics.

• KPI definition and reporting.

• Dashboard design and data visualization.

• Stakeholder management and requirements management.

• Platform established and running stably; deliberately reducing my involvement to refocus on an engineering mandate in the financial sector.
• Built an own SaaS learning platform from the ground up and scaled it to over 20,000 users (over 6,000 courses sold, B2C and B2B); end-to-end ownership from development through infrastructure to operations.
• Built a lab environment that provisions an isolated Linux container per user (Docker, Traefik, Go), including automatic provisioning and a dedicated subdomain per user.
• Integrated LLM features into the product and accelerated development end-to-end with AI-assisted workflows (Claude Code, Codex); CI/CD with automated tests.

Project: SCS (Settlement / Clearing Services)

Settlement platform serving multiple trading and clearing venues — counterparty risk safeguarding, settlement volume reduction, central risk management, and post-trade anonymity.

Technologies: Java 17, Spring Boot 3, Microservices, Spring Data JPA, SonarQube, Fortify (SCST), Mockito, Jenkins, OpenShift, Maven, Podman, GitHub, JIRA, Liquibase, Swagger, AMQP, Apache Camel, Terraform, PostgreSQL, Instana, Graylog.

• Identified and remediated CVEs in third-party libraries using SCA tooling, strengthening the security posture of production components.
• Maintained 90% code coverage with SonarQube, improving code quality and reducing production defects.
• Built and customized Helm charts and values.yaml configurations across 3 environments (ACT, SIMU, PROD), increasing deployment flexibility and consistency.
• Enabled mTLS for database authentication and message broker connections, enforcing encrypted, certificate-validated communication.
• Designed and deployed microservices with asynchronous, REST-based communication between components.
• Automated build and continuous integration pipelines using Maven and Jenkins.
• Used Podman and OpenShift for container orchestration and Liquibase for database version control.
• Optimized Java code and implemented EHCache-based caching, improving application performance.
• Managed application images, JAR versions, and dependencies via DBAG Artifactory Repository Manager.

• Implementation of specified DevOps solutions to automate infrastructure (Terraform, Bicep, CloudFormation, Ansible) on-premises datacenter (Ovirt, Proxmox, Ceph Cluster, MinIO) and private cloud.
• Administration, configuration and implementation of CI/CD DevOps pipelines (GitLab, GitFlow) to support development process (Artifactory, Prometheus, Istio, service mesh, Helm Chart, OpenShift (Red Hat Enterprise) / Kubernetes cluster), Red Hat Satellite.
• Administration, setup, monitoring and patching of Linux infrastructure based on Red Hat Enterprise for Dev, Test and QA.
• Use of Scrum and Kanban methods.
• Administration, configuration and implementation of security standards for deploying on Dev, Test, QA and Prod stages of the new ePA applications.
• Development of new plugins and add-ons needed on current infrastructure.
• Database support.
• Data analytics support (Python, Spark, Pandas, Power BI, Splunk Enterprise).
• Implementation of best practices for DevSecOps and BizDevOps using GitOps (ArgoCD), Streamlit framework, Semaphore Ansible UI.
• Configuration and testing of iperf, uperf, sysbench using benchmark-operator for external source data and IoT/MDM devices, creating reports via ELK / OpenSearch.
• Building a new Databricks platform to collect and analyze big data from different sources and IoT devices into Hadoop framework (Python, Pandas, PySpark, Power BI, Apache Airflow).
• Building backend data aggregation and processing to automate configuration deployment between different OpenShift clusters and big data framework (Python, Pandas, PySpark, Apache Spark, PostgreSQL, Django 2, Ansible Automation, Jira JSM).
• Building a new ML pipeline platform using Kubeflow, TensorFlow, KServe.
• Data extraction, transformation and loading from different data sources including structured and unstructured data to analytic DWH / big data cluster using Python, Pandas, Polars, Power BI, Django backend and PostgreSQL.
• Setup of new DevOps Test and QA HashiCorp Vault cluster for PKI and IAM.
• Configuration and testing of automated patching based on CVSS score, SIEM-integrated CVEs.
• Use of Nexpose and InsightVM to scan vulnerability events in network, host, container and application.
• Design and implementation of secure and scalable AWS architectures including VPC, EC2, S3, RDS and Route53 and similar setups on Azure and GCP.
• Automated system provisioning and deployment using CloudFormation templates.
• Configuration of IAM roles, policies and permissions to ensure secure access control.
• Patch management, backup automation and disaster recovery setup on AWS infrastructure.
• Monitoring and optimization of system performance using AWS CloudWatch and AWS Trusted Advisor.
• Support of VMware services (vSphere, Aria, Horizon) and the virtual desktop environment.
• Development and maintenance of CI/CD pipelines using Jenkins, GitLab CI/CD and AWS CodePipeline with interface to Nutanix.
• Configuration of AWS CloudWatch to monitor application performance and system events.
• Planning and execution of migration of on-premises applications to AWS cloud platforms.
• Deployment of containerized applications using Docker and Kubernetes in AWS environments.
• Deployment of internal software packages between availability zones using AWS CodeDeploy.
• Building and deploying ML models using Scikit-learn, XGBoost and Spark MLlib including hyperparameter tuning, model evaluation and production deployment.

• Coached teams in Agile methodologies and Scrum framework implementation.
• Aligned the product roadmap with business goals such as increasing bookings, improving user experience, and expanding supplier integrations.
• Collaborated with developers and third-party providers to ensure smooth API integration and end-to-end functionality.
• Created and continuously refined the product backlog with user stories, bugs, and technical improvements.
• Prioritized backlog items based on business value, revenue impact, and regulatory deadlines.
• Worked closely with backend and frontend teams to clarify dependencies and prioritize technical debt.

• Introducing 5 different process applications for various teams

• Release planning: scope and time management

• Resource/capacity planning

• Conducting sprint planning / retrospectives

• Increment planning (multiple sprints)

• Preparing steering committee meetings / reporting to the executive board

• Coordinating / aligning with external suppliers / deliveries

• Multi-project resource planning

• Aligning with the business unit and development team

• Identifying best practices with IBM BAW

• Cost control and planning for the project team and external service providers

• Collecting KPIs using LogScale

• Analyzing application errors with LogScale / queries

• Defining user stories / aligning requirements with the business unit and development team

• Testing and defect tracking

• UI/UX design of the application

• Preparing and facilitating brown-paper workshop

• Test concept, test data, test organization, test execution

• Recording team velocity / metrics

• Executing tests

• Scripts for automated testing

• Organizing tests with the business unit and IT

• Recording and prioritizing defects

• Setting up and operating the application

• Setting up application monitoring with LogScale dashboards

• Checking health endpoints with PowerShell

• Post mortem analysis

• Setting up incident management

• Setting up problem management

• Analyzing errors using LogScale queries and dashboard

• Pre-processing data for AI

• Conducting evaluation with AI language models (Meta Llama 3.3 LLM and deepset Haystack) and RAG

• Installing runtime environments for LLMs (large language model)

• Evaluating various LLMs

• Installing RAG (retrieval augmented generation) and integrating with LLM

• Extracting unstructured data with LLM and RAG

• Project based on IBM BAW (Business Automation Workflow), WebSphere Liberty, Domea, d.3, REST, LogScale (formerly Humio), Swagger, PowerShell, JIRA, Confluence, Lucom Interaction Platform (LIP), Mattermost, Jabber

• Introduction of methods for developing and automated deployment of cloud-native software and machine learning applications in OpenShift clusters
• Development of various programs in Python
• Technologies: Kubernetes, OpenShift, Kustomize, ArgoCD, Tekton, Docker, PodMan, Airflow, IntelliJ, PyCharm, Git, Bitbucket, Jira, Confluence, Python

• Provided consulting for modernizing legacy applications
• Delivered critical features under tight deadlines for backend and frontend
• Technologies: C#, .NET, WPF, WCF, REST, Angular, MS SQL Server