Amazon SQS Experts in Berlin

• Creation, maintenance and hardening of Kubernetes clusters employing Ansible and ArgoCD
• Keywords: Ansible, AWX, Kubernetes, NetApp, Prometheus, CI/CD ArgoCD, SSO, Fluent-bit, HAProxy, Calico, Keycloak, oauth2-proxy, SealedSecrets, kubeseal, Aqua kube-bench, CIS-Benchmarks, Aqua Trivy operator

• Drive migration of enterprise authorization platform from Styra DAS to open-source OPA via Skipper (Zalando's Golang-based ingress proxy) integration
• Optimise k8s resources and integrate native Prometheus metrics with OPA
• Migrate from internal monitoring solution to Prometheus CRs + Dash0

Tech Stack: Java/Kotlin, Golang, Python, Spring Boot, AWS, Kubernetes, Docker, OpenTofu, Prometheus, Grafana

• Delivered AI and data science solutions, including LLM-based chatbots and data pipelines, improving operational efficiency.
• Collaborated on product features, achieving measurable impact and maintaining strong client relationships.

• Working on the next iteration of tonbo to make it the most flexible in-process analytical database in the market that scales and is operated with strong availability

• Introduced object scope cache to the remote storage layer to avoid I/O churn

• Working on refactoring WAL to support remote storage

• Taking care of the health of the systems as well as designing the operational story and bringing them to production

• Technologies: LSM, WAL, Arrow, Parquet, Rust

• Consulting an NGO in the field of data center sustainability in publicly funded projects (BMUKN with NADIKI and Umweltbundesamt with SIEC)
• Development of Python APIs and web applications, deployment on AWS/ECS with Terraform
• Collecting power consumption metrics for servers, CPUs, GPUs running AI workloads
• Technologies used: AWS, EC2, ECS, Fargate, CloudMap, VPC, Route53, Lambda, EventBridge, CodeBuild/CodePipeline/CodeDeploy, Terraform, Docker, Linux, Bash scripting, Python, Flask, SQLAlchemy, SQL, MariaDB, InfluxDB, Telegraf, Prometheus, Zabbix, Kubernetes, Letsencrypt, certificate management

• Bootstrapping a CloudOps team and building a multi-cloud provider backend for a low-code Internal Developer Platform (IDP) with env zero

• Introducing user story mapping, ADRs, milestones, and backlog management

• Designing and developing core APIs, setting up CI/CD pipelines, OpenTofu/Terraform scripts

• Representing and communicating the team with third-party stakeholders (e.g. env zero)

• (Cross-)team coaching on DevOps, software design, Terraform, Golang, and agile practices

• Project 1: Multi-Tenant SaaS Platform: Data Integration & Pricing Management
• Objective: New development of ELT pipeline (replacement for Java 6 legacy), integration of heterogeneous source systems (CSV, Excel, Email, external DBs), event-sourcing for complete auditability, multi-tenant architecture for tenant-capable data processing
• Challenge: Processing millions of records daily, audit compliance, data isolation between different tenants
• Solution: Stakeholder workshops for requirements analysis, event-driven architecture with Axon Framework and Apache Kafka, AWS services (EC2, S3, Lambda, SQS, API Gateway) for cloud integration, PostgreSQL with tenant-specific schemas for multi-tenant data isolation, REST API design with Spring Boot for external system integrations, comprehensive testing strategy (JUnit, Spring Test, Postman, PACT, ArchUnit)
• Results: ELT performance improved from 30+ min to 1-5 min; 2-3 hours daily saved through workflow automation; 10-20 hours/week saved through event-sourcing auditability; 100% audit compliance; secure multi-tenant data isolation for 10+ tenants
• Project 2: Multi-tenant CRM System Modernization
• Objective: Migration of CRM system (20+ years PHP/MySQL) to Java microservices, Domain-Driven Design implementation, establishment of Test-Driven Development, multi-tenant-capable SaaS architecture for multiple customer tenants
• Challenge: Remodeling complex business logic, no existing test culture, scalable tenant management with data isolation
• Solution: Comprehensive testing strategy (JUnit, Spring Test, Postman, PACT, ArchUnit), multi-tenant architecture with tenant-specific databases, REST API design with Spring Boot for cross-tenant integration, Kubernetes and Docker for container orchestration
• Results: 2× performance improvement; deployment time reduced from 40+ min to 5-7 min; migration without production outages; scalable multi-tenant solution for 15+ customer tenants
• Technologies: Java, Spring Boot 3.x, Angular, Apache Kafka, AWS (EC2, S3, Lambda, SQS, API Gateway), PostgreSQL, Axon Framework, Kubernetes, Docker, GitLab CI, REST API

• Developed a Proof of Concept for distributed tracing using OpenTelemetry within a microservices architecture, enhancing system observability and reducing mean-time-to-resolution for issues.
• Built and maintained backend services using Java and Spring Boot, ensuring high reliability and performance for payment transaction workflows.
• Implemented comprehensive automated testing with JUnit and Mockito, achieving 95% test coverage to ensure code quality and maintainability.
• Gained insight into payment transaction workflows, validating end-to-end system reliability and gaining domain knowledge in financial processes.
• Tech used: Java, Spring Boot, Microservices, REST API, Kafka, Grafana, Datadog, Docker, MongoDB

• Heycar is a leading automotive platform redefining the used car market through intelligent data pipelines, multi-tenant services, and dealer-focused tooling. I led initiatives across backend architecture, data ingestion, and identity management to enhance scalability, reliability, and developer productivity.
• Ingestion Platform: Designed a unified ingestion platform with YAML-based configuration, enabling new dealer data pipelines to be onboarded without code changes, cutting setup time from ~2 months to 2-3 days and improving scalability by 40%.
• Keycloak Leadership: Acted as the company's Keycloak expert, scaling it for multi-tenant identity management and extending functionality with custom plugins and delegated admin APIs.
• Back-Office Tooling: Developed a back-office application integrated with Salesforce, enabling dealers to manage inventory, convert leads, and handle support requests in real time.
• Multi-Tenant Migration: Collaborated across backend teams to migrate Heycar's core services into a unified multi-tenant cluster, ensuring high availability.
• Frontend CI Optimization: Optimized monorepo delivery by implementing CircleCI dynamic config with NX, deploying only affected UI projects and drastically cutting build times.
• Observability & Mentorship: Enhanced monitoring and release reliability while mentoring backend engineers and improving code review standards.

• Led the implementation of a critical backend initiative for the offer teasing feature, resulting in a 10% increase in users actively seeking counter offers.
• Contributed to high-impact features such as instant advice, customer ratings, and automatic contract switching, leading to increased user engagement and conversion rates.
• Built a gRPC service to integrate internal systems with the ERP platform, improving the reliability and observability of data exchange.
• Refactored parts of the legacy Ruby codebase into a more maintainable and scalable Elixir-based architecture.
• Delivered a greenfield project from concept to production on a new stack, integrating with internal services and managing infrastructure setup and deployment.
• Collaborated closely with the front-end team, product managers, and cross-functional team members to ensure the seamless integration of backend features, fostering effective communication and collaboration across disciplines.
• Stack: Ruby, Ruby on Rails, Elixir, OTP, Phoenix, REST, GraphQL, gRPC, PostgreSQL, AWS, Cognito, Lambda, SNS, SQS, Terraform, Helm, Docker, CI/CD, Grafana, Prometheus, Git, Agile Methodology.

• Designed and deployed scalable REST APIs for enterprise clients
• Led migration of legacy systems to modern maintainable system, reducing deployment time and enabling daily deployments
• Mentored junior developers and collaborated cross-functionally to align technical roadmaps with business goals, improving team velocity by 50%.
• Tech Stack: PHP (Symfony), Golang, PostgreSQL, MySQL, GCP, Terraform, Kubernetes

• Development of React.js / Next.js web application, displaying live sensor data and optimized routes on interactive maps.
• Architected and managed Node.js backend services in Docker containers integrated with Kafka, responsible for order management and routing.
• Guided and supported junior developers in their professional growth as team lead developer.
• Technologies: node.js, React, TypeScript, Postgres, Docker, Kafka, Github CI, ArgoCD

• Built a warehouse native customer data platform from scratch
• Successfully onboarded the first customer
• Built the first engineering team of 3 engineers
• Raised 1M€ in venture capital

Training course with exam for Spring Certified Professional.

• Environment: Spring Boot 3, Spring Framework 6, IntelliJ