Nils Rommelfanger

Freelance Backend Software Engineer Continuous Delivery

📍 Amel, Belgium 📧 nelhimoud@gmail.com 📞 +32 (0) 456 950004

About Me

I am a software engineer with a strong Continuous Delivery mindset and 20 years of experience in backend technology. I bring a comprehensive skill set spanning architecture, clean code practices, automated testing, legacy code refactoring, deployment pipelines, operations, and observability.

I firmly believe that Continuous Delivery—TDD, feedback loops, and automation—are essential not only for delivering high-quality software but also for achieving high development efficiency. By continuously improving every aspect of the codebase, I ensure sustainable and efficient software development.

Core Competencies

Languages & Frameworks: Java • Kotlin • Spring Boot

DevOps & Cloud: Kubernetes • Docker • AWS • CI/CD (GitHub Actions, Jenkins) • Terraform • Helm • Infrastructure as Code

Architecture & Practices: Cloud Native • 12 Factor Apps • Microservices • Clean Code • Refactoring • Legacy Code Modernization • TDD

Testing & Quality: JUnit • Mockito • Automated Testing • Quality Assurance • Code Reviews

Observability & Security: Distributed Tracing (OpenTelemetry) • Logging • OAuth2/OIDC • Secure Coding

Databases & Messaging: PostgreSQL • MySQL • MongoDB • Redis • Apache Kafka • RabbitMQ

Methodologies: Agile • Scrum • Continuous Delivery • DevOps —

Why Work With Me?

With 20 years of experience across diverse domains—from IoT platforms and autonomous systems to financial services and e-mobility—I bring deep technical expertise combined with a pragmatic, results-oriented approach.

What I Deliver:

  • Immediate Impact – I onboard rapidly and contribute from day one (joined projects 1 month before deadline and helped teams ship on time)
  • Legacy Rescue & Modernization – I turn struggling codebases into maintainable, efficient systems while keeping them stable
  • Scalable, Observable Systems – I build cloud-native architectures that are robust, performant, and easy to operate
  • Fast, Efficient Delivery – I practice and promote CD principles, keeping software always release-ready so changes ship rapidly and efficiently while minimizing costly bugs and manual testing overhead
  • Problem-Solver, Not Just Coder – I question requirements and challenge existing complexity. My focus is solving real problems, which often means simplifying or removing code rather than building more
  • Deep Observability – Comprehensive logging and tracing reduce problem analysis effort and minimize mean time to recovery
  • Team Acceleration – I mentor developers and establish best practices that elevate entire teams

Whether you need someone to architect a greenfield project, rescue a critical system, or accelerate your team’s delivery—I’m ready to deliver results.

Professional Experience

Senior Software Engineer | Actico GmbH

May - August 2025

Joined the project one month before deadline and immediately contributed from day 2, helping the team meet their goals comfortably.

  • Improved exception logging, reducing boilerplate by 80%
  • Resolved bugs related to sorting and translation
  • Enhanced test quality to validate correct behavior

Tech Stack: Java 17, Spring Boot, JUnit, Mockito, Postgres, Liquibase, JPA, Spring Security, Mapstruct, OpenAPI, Grafana, CI/CD

Senior Software Engineer | Ously Games GmbH

June - August 2024 (layoff due to financial problems)

  • Refactored codebase to remove unnecessary features and reduce maintenance overhead
  • Implemented reusable streak/mission/reward system to boost user engagement and retention

Tech Stack: Java 21, Spring Boot, JUnit, Mockito, MySQL, Liquibase, Redis, RabbitMQ, AWS, CI/CD

Cloud Engineer | Morgenwerk GmbH

June 2023 - March 2024

Developed navigation algorithm for warehouse AGVs from scratch.

  • Designed adapted A* algorithm for planning hundreds of robots in 3D storage space with >99% storage density
  • Performance tested for up to 10,000 AGVs
  • Comprehensive testing with JUnit and Mockito
  • Implemented deployment pipeline with GitHub Actions

Tech Stack: Kotlin, Spring Boot, JUnit, Mockito, AWS, MQTT, A* algorithm, CI/CD

Senior Software Engineer | Clevershuttle

April 2022 - May 2023 (company bankruptcy)

Platform for on-demand shared rides.

  • Developed microservices with Spring Boot and Kotlin
  • Designed and implemented multi-tenancy support
  • Improved test coverage and observability (OpenTelemetry)
  • Provided mentorship to junior developers
  • Contributed to architecture decisions

Tech Stack: Java 17, Spring Boot, Kafka, MongoDB, Kubernetes, AWS, GitHub Actions, CI/CD

Senior Software Engineer | Bosch.IO

2008 - 2022

Worked on multiple internal IoT projects including:

Robert Bosch Semantic Stack

Comprehensive product lifecycle data platform.

  • Developed catalog microservice
  • Architecture and design work
  • Ensured CI/CD with automated testing

Tech Stack: Java 11, Spring Boot, Spring Security, Kubernetes, Docker, AWS Neptune, RDF, OAuth2, OpenTelemetry

Bosch IoT Suite Portal

User and subscription management for SaaS offerings.

  • Full-stack development and operations
  • Implemented org/team-based access management
  • Refactored legacy codebase
  • Mentored junior developers

Tech Stack: Java 11, Spring Boot, Hibernate, Kubernetes, Docker, Thymeleaf, AWS, OAuth2, Ory Hydra, New Relic, Dynatrace

Central Authorization Server

OAuth2-based authentication/authorization replacement.

  • Designed and built authorization server (Keycloak → Ory Hydra)
  • Built REST API for resource registration
  • Analyzed and resolved scalability issues
  • Migrated from EC2 to EKS
  • Infrastructure as Code with Terraform and Helm

Tech Stack: Java 8, Spring Boot, Kubernetes (EKS), Terraform, Helm, OAuth2, Keycloak, Ory Hydra, Distributed Tracing

Bosch Permission Service

SaaS authentication and authorization solution.

Tech Stack: Java 8, Spring Boot, PostgreSQL, Docker, Jenkins, Splunk, ELK Stack

Bosch Thermotechnik

B2C/B2B portal for heating appliances.

  • Backend development
  • Remote collaboration with teams in Germany and Portugal

Tech Stack: Java 8, Vert.x, MongoDB, RabbitMQ, Cloud Foundry, OSGI

Indego Autonomous Lawn Mower

Backend for cloud-connected lawn mowers.

  • Sole developer for ~1 year
  • Designed smart mowing based on weather forecasts
  • Implemented OTA firmware update management
  • Performance profiling and comprehensive logging

Tech Stack: Java 8, Vert.x, RabbitMQ, Cloud Foundry, MongoDB, Splunk, ELK Stack

E-Mobility Charging Broker

Unified billing across charging providers.

  • Introduced application logging from scratch

Tech Stack: Java 8, Spring, Tomcat, Oracle Cloud Foundry

Additional Projects

  • Telemedicine: Migrated SQL to Hibernate/Criteria API
  • Finance Suite (Vontobel Bank): Maintained 12-year legacy codebase, optimized complex Hibernate/SQL queries
  • Finance Suite Product: Transaction monitoring for compliance and fraud detection

Earlier Roles

Software Engineer | Indextraffic (2007-2008) Co-founder - Portal engine for SEO-optimized pages

Software Engineer | Suchtreffer (2005-2007) Backoffice tools for AdWords campaigns and custom ORM mapper

Education

Diplom Informatiker (FH) | HTWG Konstanz 2001-2005: Software Engineering - Artificial Intelligence 1999-2001: Technische Informatik

Allgemeine Hochschulreife | Bodensee Gymnasium Lindau 1990-1997

Languages

  • German: Native
  • English: Fluent

Interests

Family • Cooking • Gardening • Technology • DIY

Let’s build something great together.