09.01.2026 aktualisiert

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Legacy Modernization Expert · Systems Engineer (Python / Clojure) · Senior Software Engineer

Mülheim an der Ruhr, Deutschland
Deutschland
Master of Engineering
Mülheim an der Ruhr, Deutschland
Deutschland
Master of Engineering

Profilanlagen

Hendrik_Levering_Legacy_Modernization_Expert_CV_2025.pdf
Hendrik_Levering_Legacy_Modernisierung_Experte_Lebenslauf_2025.pdf

Über mich

Senior Software Engineer (10+ J.). Modernisiere Legacy-Systeme in Energie/IoT/B2B-SaaS: Komplexität raus, Performance rauf, klare Boundaries, schlanke Infra/CI. Tech: Python, Clojure, FastAPI, Postgres, Docker. Ich mache fragile Plattformen wieder schnell und wartbar.

Skills

Amazon Web ServicesSystems EngineeringAutomatisierungMicrosoft AzureClojureSaasBeratungContinuous IntegrationDatenmodellUmwelttechnologieGitHubPythonPostgreSQLMQTTLeistungssteigerungSoftware ArchitecturePrometheusDatadogTestenGrafanaInternet Of ThingsFastAPIEvent Driven ArchitectureCADdy++Gitlab-CiKubernetesApache KafkaDomain Driven DevelopmentFunktionale ProgrammierungRefactoringDocker
Python, Clojure, ClojureScript, FastAPI, Datomic, RamA, Postgres, Legacy-Modernisierung, Refactoring, Performance-Optimierung, Software-Architektur, Functional Programming, REPL-Driven Development, Interne Tools, Editoren, Automatisierung, Datenmodellierung, DDD, Event-Driven Architecture, IoT, Kafka, MQTT, Kubernetes, K3s, Docker, Hetzner, Caddy, AWS, Azure, GitHub Actions, GitLab CI, Observability, Prometheus, Grafana, Datadog, CI/CD, Property-Based Testing, TDD, BDD, SaaS, Industrial IoT, Energiesektor, Umwelttechnik, Consulting

Erfahrung

Berufserfahrungmehr als 10 Jahre
Freelancer seit2021

Sprachen

DeutschMutterspracheEnglischverhandlungssicher

Projekthistorie

Role: Senior Modernization Engineer – Legacy Web App Performance & Refactoring (Energy Sector)

Energie, Wasser und Umwelt

>10.000 Mitarbeiter

  1. Re‑architected a legacy web application and modularised tightly‑coupled components, cutting response times from several seconds to <50 ms in a representative production scenario.
  2. Removed redundant layers and over‑engineered patterns, making the system simple enough that internal teams can now add features independently.
  3. Tech & patterns: Python, Java, Spring Boot, TypeScript, Vue.js, AWS SQS, REST, GitHub Actions, performance profiling, caching, modularisation, CI/CD hardening

Role: Senior Backend & Integration Engineer Legacy Web App + IoT Integration

Energie, Wasser und Umwelt

1000-5000 Mitarbeiter

  1. Modernised a legacy platform and designed a simple, robust data flow to integrate distributed customer systems into an IoT backend.
  2. Re‑designed data flows and hardened MQTT processing for reliable, near‑real‑time monitoring.
  3. Tech & patterns: Python, Kafka, MQTT, Mosquitto, GIS, IoT, event‑driven architecture, GitHub, Linux, CI/CD

Role: Lead Developer & Architect – SaaS Editor for Organic Shapes (G‑code Generator)

Konsumgüter und Handel

< 10 Mitarbeiter

  1. Designed and implemented a browser‑based editor and custom slicer that lets users create organic single‑wall shapes, validates manufacturability, and generates G‑code for 3D printers.
  2. Built a small, understandable platform: K3s cluster, Git‑based deployments, observability, and functional UI – optimised for low maintenance and easy extension.
  3. Tech & patterns: Clojure, Python, React, ThreeJS, Redis, Postgres, K3s, Grafana, Loki, Prometheus, ArgoCD, AWS S3, Docker, functional core/imperative shell

Role: Senior Backend Engineer – Ecosystem Analysis Platform

Energie, Wasser und Umwelt

10-50 Mitarbeiter

  1. Created a scalable but simple backend that orchestrates long‑running compute tasks and external data sources, replacing ad‑hoc scripts with a predictable system.
  2. Introduced clear data models and APIs (REST/GraphQL), improving onboarding and reducing operational incidents for the client’s engineering teams.
  3. Tech & patterns: Python, FastAPI, Django ORM, GraphQL, Kubernetes, Redis, AWS SQS/EKS, Postgres, Docker, Terraform, GitLab CI, property‑based tests

Role: Senior Engineer – Expert Suite Usability & Automation

Industrie und Maschinenbau

>10.000 Mitarbeiter

  1. Simplified a complex expert software suite, replacing fragile manual workflows with automated flows and clearer UIs, and hardening it against misuse.
  2. Focus on refactoring, CI/CD and removing unnecessary steps from core user journeys.
  3. Tech & patterns: Python, Bash, C++, Qt, GitLab CI/CD, Linux, test‑driven development

Werkstudent

Siemens AG

Industrie und Maschinenbau

>10.000 Mitarbeiter

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