Apache ZooKeeper Experts in Germany

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.
• 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.
• Optimized a high-volume REST API (~200K requests) by reducing response time from 3s to 2s (33% improvement), boosting throughput and reliability under production load.
• Automated build and continuous integration pipelines using Maven and Jenkins.
• Orchestrated containerized workloads on Podman/OpenShift and governed schema evolution with Liquibase, ensuring reliable, repeatable deployments across all environments.
• Optimized Java code and implemented EHCache-based caching, improving application performance.
• Streamlined release management by governing application images, JAR versions, and dependencies through DBAG Artifactory, ensuring version consistency and audit traceability across environments

• It is like a startup within REWE, where we have to build a new forecasting system on Google Cloud Platform from the scratch. Although, officially my role is called MLOps, my actual tasks also include development of data processing pipelines (data engineering) and data scientists tasks such as feature engineering and model trainings.
• GCP: Terraform (tofu), Vertex AI (Kubeflow), Cloud Run, IAM, Google Cloud Storage, BigQuery, Artifact Registry
• Data engineering: Snowflake as the main data warehouse, Terraform, DBT for data model implementations
• CI/CD: GitLab. We have built a CI/CD pipeline that automates deployments of new releases up to production environment
• Development of feature store and data synchronization between environments
• Data science: evaluation of different forecasting models, including CatBoost, Contextual Gamma and Random Forest; implementation of training pipelines using Kubeflow on Vertex AI; scaling and development of an event-driven interface using Kafka as a forecasting service; evaluation of MLFlow for model tracking and model registry
• Implementation of REST API using KeyCloak OAuth2 and OpenID (JWT)
• Monitoring: implementation of dashboards with Grafana, Prometheus, Mimir, Streamlit and Loki to monitor prediction metrics, GCP and Snowflake costs for pipelines, and system metrics
• Development of Copilot Agent Skills

• Led engineering strategy development and execution across multiple teams (Engineering, DevOps, SysAdmin, QA), defining quarterly OKRs and roadmaps to align with business objectives.
• Established comprehensive engineering excellence framework including coding standards, career progression paths, and critical operational policies.
• Successfully conducted technical due diligence during investment rounds, presenting technology infrastructure to potential investors.
• Developed and implemented key organizational policies including incident management, deployment guidelines, and security protocols.
• Streamlined recruitment process and managed performance reviews, resulting in improved team composition and capabilities.
• Architected and implemented full-stack solutions using TypeScript, Node.js backend and Next.js frontend with Styled Components.
• Designed and optimized serverless architecture utilizing AWS Lambda, Step Functions, State Machine, ECS, API Gateway, and multiple databases (DynamoDB, MongoDB, Postgres, MariaDB, OpenSearch).
• Implemented GraphQL for frontend requests and REST APIs for backend services, improving system connectivity and data flow.
• Established robust CI/CD pipelines using GitHub Actions and Jenkins, incorporating quality gates and security checks.
• Integrated SonarCloud for static code analysis, enhancing code quality across all repositories.
• Spearheaded infrastructure stability and security improvements while optimizing operational costs.
• Implemented automated testing framework using Jest for backend/frontend and Playwright for E2E testing.
• Created reusable tooling modules for logging, database connectivity, parameter store integration and reusable libraries.
• Designed and implemented microservices architecture using AWS ECS, documented with OpenAPI specifications.
• Enhanced creation and deployment processes through standardized templates and automated pipeline creation.
• Successfully delivered multiple projects on schedule while maintaining high quality standards and best practices.
• Conducted regular 1-on-1s and mentoring sessions, fostering team growth and professional development.
• Participated in cross-functional management meetings, ensuring alignment between technical initiatives and business goals.
• Identified and addressed knowledge gaps through targeted mentoring and training programs.
• Implemented atomic design principles for frontend development, improving component reusability and maintenance.

• Optimizing the online shop search function based on Magento and OpenSearch
• Advising on eliminating search pain points (composite search, case-insensitive search)
• Data modeling of products (parent) and items (child)
• Workshops to convey domain-specific search understanding

• Head of overall technical integration NSC (National Secure Cloud, project with approx. 60 employees).

• Technical integration of all subprojects into one product, definition of interfaces and basic components of a cloud including hardware, technical architecture of the IABG platform.

• Development of a Cloud Management Platform (CMP) capable of creating private/mixed clouds of any complexity based on a textual description with one click or interactively.

• CMP also includes the complete hardware management lifecycle.

• Kubernetes, OpenStack and Hadoop are used as the foundation.

• The management layer includes Harbor, Gitea, Longhorn, Keycloak, Rancher and Jenkins, which are configured automatically.

• Private cloud can run any customer workloads, including a full Hadoop layer with HDFS, Spark, MapReduce, Mesos, HBase and around 20 additional ML/DL technologies.

• Hadoop worker clusters can also be installed automatically without Kubernetes on bare metal or commodity hardware.

• OpenStack with Nova, Neutron, Ironic, Swift, Cinder, Ceph.

• Development of a Java application Rudi: SOAP, REST, containers, DB.

• Technologies: Kubernetes (K3s, Rke2, Minikube, Harbor, Gitea, Jenkins, Longhorn, Keycloak, Rancher), OpenStack (Nova, Neutron, Keystone, Swift, Ceph, Cinder, Sahara, Magnum, Kayobe, Kolla, Bigrost, Ironic), Hadoop (HDFS, Ambari, Solr, Livy, Ranger, YARN, Tez, HBase, Kafka, Hive, Zookeeper, MapReduce, Spark, Oozie, Flink), virtualization (Kubernetes (K3S), VMware, Oracle), scripting (Ansible, Puppet, Juju, Shell, Groovy, Gradle, Maven).

• Responsible for software engineering and DevOps in the Data & AI Platform - Intake and PubSub projects at STACKIT, the cloud provider of the Schwarz Group.
• Technologies: Golang, Kubernetes, Kubernetes operators, OpenAPI v3, REST API, Azure DevOps, CI/CD, k6, Kafka, Strimzi, Apache Iceberg, RBAC, IAM, Terraform, Helm, Infrastructure automation, Load balancing, Traefik, ArgoCD, kuttl, Kyverno chainsaw, Kustomize, Velero, Prometheus, Grafana, Checkly / Playwright (TypeScript), NATS/Jetstream, WebSockets, gRPC, SSE

• Setting up and enhancing an international subscription management system

• Migrating and decommissioning a Hybris-SAP system and integrating Zuora

• Implementing numerous interfaces to various systems (external and internal)

• Setting up and improving monitoring with Grafana, Prometheus, and Databricks

• Introducing logging with Loki

• Implementing business requirements using jQuery, Thymeleaf, Spring Boot, Java, Go, and Python

• Adjusting and extending the GitLab CI pipelines

• Setting up and extending infrastructure as code with Terraform and ArgoCD on AWS

• Setting up and running E2E and performance tests

• Expanding the Databricks business intelligence solution to provide various KPIs

• Responsibilities: Architecture, DevOps, development, unit tests, coaching employees and apprentices, E2E, smoke, and integration tests, agile methods consulting (Kanban, Scrum)

• Technologies and methods: Java, Go, Kotlin, Node.js, Spring Boot, SOAP/REST, Quarkus, Thymeleaf, Vaadin, Slack, Jira, Confluence, IntelliJ, GitLab, SQS, Kafka, AWS, Kubernetes, Terraform, Maven, Gradle, GitLab CI, Databricks

• Teaching JavaScript, HTML, CSS, React, NodeJS, MongoDB, MariaDB, and Express
• Designing and preparing lessons
• Classroom teaching and one-on-one coaching