Software Developers in Hamburg

• 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

traigo is VTG's digital rail logistics and fleet management platform. It processes large volumes of telemetry, mileage, geofence, sensor and wagon-movement events in near real time and provides operational services for rail logistics customers across Europe.

As part of Team Customer Selfcare, I worked on the design, implementation, optimisation and operation of large-scale backend services and event-driven processing pipelines — covering both feature development and operational ownership of business-critical production systems. I also regularly acted as first responder for production incidents, data inconsistencies and performance investigations across multiple distributed services.

• Design and implementation of event-driven backend services.
• Migration and replacement of legacy processing pipelines.
• Development of replay / rebuild mechanisms for large event datasets.
• High-throughput asynchronous event processing on SNS / SQS.
• Database and query optimisation for PostgreSQL and DynamoDB.
• Design of scalable read / write models and aggregation pipelines.
• Production troubleshooting and operational support.
• Performance tuning and infrastructure scaling.
• Design and stabilisation of integration and system tests.
• Technical concepts, architecture documentation, and cross-team collaboration.
• Support the further development of existing GitLab CI/CD pipelines

Geofence & Wagon Stay Processing

• Algorithm to detect vehicles within geofences (entry, exit, dwell time).
• Event sourcing with guaranteed chronological order within the affected time window.
• Refactored geofence event and wagon-stay processing logic for performance.
• Resolved race conditions and event-ordering problems in distributed services; server-side filtering, aggregation and optimised query pipelines.
• Repair and replay tooling for corrupted or inconsistent movement data.

Fleet Metadata & Mileage

• Modernised the service; migrated storage from DynamoDB to PostgreSQL to improve traceability and accelerate new features.
• Scalable mileage aggregation and replay mechanisms.
• Read / write models and optimised queries for high-volume mileage calculations.

Sensor & Telematics Integration

• Integrated telemetry and sensor processing pipelines.
• Snapshot and state-calculation logic for sensor systems.
• APIs and persistence models for wagon sensor data; data-quality improvements.
• Further development of a service using gRPC for intra-service communication.

Movement Segment Processing & Routing

• Migrated services to new movement-segment event streams.
• Built replay and rebuild tooling for segment correction.
• Optimised throughput and reliability for high-volume event processing.

Condition Monitoring & Wagon Analytics

• APIs and backend services for wagon condition monitoring.
• Brake-wear prediction processing and wagon analytics functionality.
• PostgreSQL views and optimised query models for operational dashboards.

Operational Reliability - First Responder

• Investigated production incidents and distributed-system failures; DLQ analysis, replay and operational recovery.
• Tuned database performance and AWS infrastructure under production load.
• Improved observability, monitoring and operational tooling.
• Supported rollout strategies, monitoring and post-deployment stabilisation.

Project:

• Migration of existing VB6 applications to C# (Web API, web app)
• Report development and risk management systems (C#, API interfaces, databases)
• Document archive (API interfaces, databases)

Team size: 9 people

• Reports for Risk and Credit Management Development and maintenance of report structures to support risk and credit decisions, including data modeling, validation, and automated delivery for business departments.
• Migration and maintenance of a legacy system to the latest version of .NET for the asset management system Planning and execution of the modernization of an existing asset management system, including code refactoring, performance optimization, test automation, and sustainable maintenance after migration.
• Replacement of the COM-based archive connection with a REST API Redevelopment of the connection of the document archive (HYPARCHIV) to a REST API based on OpenAPI/Swagger, including archiving with index and stamp fields as well as PDF export into the customer portal.
• Redesign of payment receipt processing Replacement of an existing Oracle PL/SQL process with a new implementation in C# based on a business concept, including business alignment, data modeling, and test coverage.
• Design and implementation of tests, creation of deployment pipelines, and documentation
• Further development and implementation of change requests.
• Regular code reviews within the team as well as optimization of application scalability and stability

Technologies: C#, .NET 10, ASP.NET, Unit of Work, IoC, Three-Tier Architecture, Entity Framework Core, DB First, Web API, Swagger, OpenAPI, Python, Oracle, HYPARCHIV, Azure, PowerBI, DevOps, AKS (Azure Kubernetes Service), GIT, xUnit, NSubstitute, TypeScript, Vue.js, Pinia,

Methods: agile development using Scrum

• Real-time tone detection on FPGA (~20 ms latency target) using a filter bank architecture with a fuzzy-logic decision stage, avoiding FFT due to its window-length/frequency-resolution tradeoff.
• Responsible for system integration and architecture.

• Environment: AWS, Ruby on Rails, GraphQL, React Native
• Penetration test for Backend, Android-App and iOS-App

• Developing a professional scheduler for organizations with specific detailed requirements
• Evaluating different existing software solutions
• Creating a list of technical requirements
• Implementing these requirements
• Selected technologies: WebDAV, CalDAV, Rust, Baikal, OAuth, Keycloak

• 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

• Full-stack development of a customizable SaaS platform for the real estate industry
• Running domain discovery processes to gather business requirements and derive technical specifications
• Designing and implementing core features based on a Remix MVC architecture with TypeScript, Node.js, and PostgreSQL
• Focus on usability, extensibility, and high scalability of the platform

• Development of modern web applications focusing on React and Next.js

• Implementation of e-commerce and business platforms for SMEs

• Analysis and optimization of software and data structures

• Design and development of custom IT solutions

• Structuring of data flows and system architectures

• Ongoing project work in web development and platform solutions

• Tax Advisor Platform with Client Portal and Admin System:

• Development of a web-based platform with an integrated client portal

• Implementation of a system solution including a website, admin panel, and client application

• Development of a role-based access system (admin / client)

• Implementation of document and invoice management

• Digitization of business processes

• Building high-performance frontend structures

• Integration of APIs and backend logic

• Coffee Business Platform with Admin System:

• Development of a web application for a café with administrative functions

• Implementation of internal workflows and user management

• Structuring of digital business processes

• Development of modern UI components with a focus on performance

• Shared Account Platform (Admin & Client Applications):

• Development of a scalable platform with separate applications for admins and users

• Implementation of a role-based access system

• Development of a modular frontend architecture with React and TypeScript

• Integration of API structures and data management

• Further development of the Android app "StarMoney"
• Major XML to Compose redesigns
• Introduction of new technologies and architecture
• Implementation of instant bank transfer
• Development following the agile Scrum process

• Developed a web application for horse betting
• Converted components to script syntax

• Integration of SAP Commerce Cloud with SAP Cloud for Customer
• Creation and execution of unit and integration tests
• Error analysis and bug fixing

• Designed, implemented, and deployed two new microservice components, enabling new business functionalities and supporting regulatory compliance for enterprise clients.
• Ensured business continuity and system reliability within a high-transaction, microservice-based environment, taking ownership of backend systems under dynamic business conditions.
• Identified and refactored inefficient implementations, applying cost-benefit analysis to optimize performance, maintainability, and code quality.

• Significant enhancement of the B2B React SPA software "opti.node" for commercial operations management for renewable energy plant operators
• Introduced features not previously available on the market, resulting in a significant revenue increase
• Comprehensive automated tests within Storybook
• Introduced a UI library to improve developer experience and speed up feature development by about 40%
• Clear presentation of complex commercial and legal issues, with intuitive UX and UI
• UX consulting to shorten essential interaction flows by 75%