Helm Expert in Hamburg

• Building a data integration platform for high, medium, and low voltage assets for contextual analysis of time series with master data from the SCADA control system (IEC 60870 104), INIS, and SAP.
• Responsibility for the architecture and implementation of the solution, as well as sparring partner for the Product Owner.
• Use of Kotlin, Spring Boot, Maven, TimescaleDB, PostgreSQL, liquibase, Elements IoT, Docker, Kubernetes, Grafana, Python, jupyter, and various API gateways.

• Onboarded and conducted comprehensive documentation and system analysis to assess the existing data infrastructure, facilitating rapid integration and collaboration across functional data teams (modelling, processing, reporting).
• Collaboratively defined the architecture and project structure for a central data pipeline repository, including hierarchical standards, knowledge management strategies, and role-specific responsibilities, enhancing maintainability and onboarding speed.
• Evaluated and validated open-source data routing tools (Airbyte, Apache NiFi, Dragster) for ingest and sync requirements in retail analytics, including local benchmarking and error-state testing.
• Led the design and deployment of Airbyte in Kubernetes, creating customized Helm charts, securing secrets handling, and configuring Ingress with TLS and internal DNS routing, ensuring full API and UI accessibility.
• Troubleshot and resolved Ingress controller issues, iterating through multiple stages of debugging and testing, and documented setup and replication steps for scalable reuse.
• Mapped data models to ARTS standard, supporting schema alignment for ERP and reporting use cases, and coordinated review loops to align future data processing logic.
• Drafted strategic 1-pagers comparing MinIO, Pub/Sub, and routing architectures, providing technical guidance for architectural decisions and investment planning.
• Enabled secure access and authentication mechanisms, including initial evaluation for SAML integration, cluster-level configuration reviews, and service annotation improvements.

• Technical consulting to meet regulatory MiCA requirements for a digital trading platform
• Design and development of backend components and APIs to comply with transparency and auditability requirements
• Optimization of core functions in order execution and market data delivery with a focus on performance and reliability under high load
• Conducting job interviews and structured onboarding of new developers
• Successful and timely implementation of the regulatory MiCA requirements, ensuring uninterrupted operations
• Reduction of user issues and common support requests by fixing complex backend problems
• Strengthening the development team through effective onboarding, mentoring, and knowledge sharing

• Several projects in a police context
• Model and document police procedures/projects with Archimate (as-is/to-be) in the context of P20 (BKA)
• Create software architectures with microservices
• POC development with Springboot/Docker/Kubernetes
• Project size: 10 people
• Enterprise architecture management with Togaf and Archimate
• Backend software development Springboot
• DevOps with Kubernetes
• Implemented using: Java 17/21, Springboot 3, P20 architecture, Togaf, Archimate

• Further development of the compliance products
• Responsible for the Senior Software Engineer role
• Team size: 5 - 15 people
• Tools: TypeScript, Angular 18, Node.js, Nest.js, AWS, Kubernetes/Helm Charts/Docker, GitLab (CD/CI), Elasticsearch, MySQL, OpenAI, Java, RabbitMQ

• Designed and implemented a Python-based ETL pipeline with the Dagster framework to transform raw energy data from heterogeneous sources using InfluxDB and visualizations in Grafana
• Defined time-based and dependency-based jobs
• Deployed to managed Kubernetes clusters using Helm
• Integrated InfluxDB Cloud
• Prepared data for use in Grafana, including cleaning, normalization, and time-based resampling in Python
• Developed dashboards and visualizations in Grafana
• Developed unit tests with mocking using pytest
• Set up a CI/CD pipeline in GitLab

Technologies: Python, Dagster, InfluxDB, Grafana, pandas, pytest, REST, CI/CD, GitLab, Container, Kubernetes, Helm, Docker, Cloud

• Role: Developer, Architect
• Technologies: java, typescript, golang, spring (boot, web, security, data), Angular, AWS (OpenSearch, Aurora, SNS/SQS, CloudWatch, EC2, IAM), Kubernetes, Terraform, Helm, OAuth, Keycloak, CI/CD, gradlew, Liquibase, Test Driven Development, shell scripting

• Working with developers, security, and operations teams to align requirements
• Supporting product owners and development teams in using logging and monitoring solutions based on the Elastic Stack
• Developing and standardizing log schemas as well as defining practical standards for observability
• Designing and further developing logging architectures for complex, distributed multi-tenant environments
• Connecting application and infrastructure logs as well as security tools and metrics
• Optimizing data flows and modeling for analysis and reporting purposes
• Building automated infrastructures using Terraform/Terragrunt and Ansible
• Maintaining and further developing CI/CD pipelines in GitLab as well as automated development environments in Hetzner Robot
• Operating and automating Proxmox clusters including Ceph storage
• Setting up and operating Kubernetes (k3s) clusters on Fedora CoreOS including base services such as Vault, OpenLDAP, and HA Proxy
• Implementing security-critical infrastructures according to BSI baseline protection and securing existing systems
• Supporting the operation of solutions in cloud environments (including AWS)
• Working in agile teams using Scrum and Kanban
• Technologies/ applications: Elastic Stack (Elasticsearch, Logstash, Beats/Elastic Agent, Kibana), Terraform, Terragrunt, Ansible, GitLab CI/CD, GitOps, Proxmox, Proxmox Ceph, Kubernetes (k3s), OpenShift, Helm, Kustomize, Vault, OpenLDAP, HA Proxy, Hetzner Robot systems, AWS, Prometheus, Grafana, Syslog Linux/Windows, Docker, NGINX, Apache Security & Compliance (BSI baseline protection, SIEM/SOC)

• Further development of a finance layer for subscription and one-time purchase billing and accounting.
• Technologies: Kotlin, AWS (SQS, S3, ElastiCache, Aurora), React, TypeScript, Coroutines, IntelliJ IDEA, Spring (Boot, Data, WebFlux), JUnit, Testcontainers, Cucumber, Liquibase, PostgreSQL, Webservices (REST), R2DBC, OpenAPI 3, Gradle, GIT, Docker, Netty, GitHub Actions, Jira/Confluence, arc42

• Coaching junior developers
• Further development and customer-specific extensions of a standard software product (microservices (DDD) and partly monolith)
• Interface extensions
• Web services
• Test automation
• Design
• Technologies used: Java8, Java17, TypeScript, Python, PostgreSQL, Spring (Integration, Data, Boot), JPA, AWS (Cloud, Lambda, EC2, SQS/SNS), Microservices, Fitnesse/Cucumber, Gitlab

• Responsibility for testing and quality assurance of application processes
• Creation and execution of test cases based on defined acceptance criteria
• Documentation of deviations and analysis, as well as initiation of necessary corrective actions
• Ensuring the flow of information within the team and with other specialist departments
• Maintenance and further development of test automation
• Adapting Selenium-based automation to every release and sprint change
• Extending test automation with new processes
• Performing security tests
• Identifying typical vulnerabilities (e.g. XSS, SQL injection, insecure headers) through automated tests in the CI/CD flow
• Use of technologies Selenium (including integration with security scanners such as OWASP ZAP), Unix/SQL environments and optionally Cypress, SAP, C#, Java, GitLab, Jira, Confluence, REST API, Postman, HP-ALM, SSI, Octane, WinSCP.

• Manage and operate the product data import services for the Otto merchant
• Enhance and maintain the backend systems
• Optimize and maintain AWS infrastructure
• Build a new product data import API
• Design and plan stories and features
• Conduct code reviews to ensure code quality and best practices
• Analyze and fix bugs
• Technologies: Java, Spring Boot, Kafka, AWS, Fargate, Terraform, MongoDB, Mongo Atlas, OpenAPI, GitHub, GitHub Actions, GitHub Copilot, Akhq, Debezium, JUnit, Test Containers, Hexagonal Architecture

• Operation and further development of the inventory system for booksellers (Quimus). It is an in-house development by Libri that is sold to customers as Software as a Service. The software is developed in an agile way by two developer teams (about 5 developers each). The software consists of around 25 Java microservices that mainly communicate via messaging and share a common Angular frontend. The application runs on Kubernetes in AWS.
• Technologies used: Java 17 & 21, Spring Boot 2 & 3, Hibernate, MySQL, Spring Cloud AWS, Lombok, AWS SQS, AWS SNS, AWS RDS, AWS S3, DynamoDB, Kubernetes, Docker, OpenSearch, Hibernate Search, Liquibase, Gradle, Terraform, Helm, GitLab CI, Keycloak OAuth2, TypeScript, Angular
• My focus until December 2023: Connecting additional POS systems to the inventory system. Connecting the data warehouse for report display. Extending existing features (goods receipts, invoicing, item management, ...). Operations and DevOps tasks.
• Focus from January 2024: Extracting the product search from the inventory system into a global service to use in other applications. Integrating the product search into the booksellers' online shops (also run by Libri). Importing and providing digital items in the product search.

• Budget responsibility for SEM, SMM and affiliate marketing

• Direct management and development of the 10-person Demand Generation team

• Development and implementation of the digital strategy

• Development of the supplier network

• Optimization of workflows for maximum efficiency and effectiveness

• Close collaboration with sales and marketing

• Reporting to the CEO

• Optimized lead handling by increasing capacity and efficiency without adding headcount

• Development and enhancement of the EU Salesforce ecosystem beyond own department

• Increased field sales conversion by shifting new business acquisition from outbound to inbound

• Reshaped working methods, goals and values within the team