Software Developers in Hamburg

Fiverr client

• Fixed consumer issues in a production Kafka environment.
• Analyzed consumer lag with Datadog.
• Added synthetic tests to detect issues early.

Stack: Kafka, Datadog, Consumer Groups

• Planning and implementation of digital client projects at the intersection of visual design, conceptualization, and technical implementation.

• Development and structuring of well-thought-out websites with a focus on logical user guidance (UI/UX) and functional consistency.

• Advising companies and start-ups on their digital presence and the development of sustainable systems for the long term.

• Continuous integration of modern, AI-assisted development processes (Vibe Coding) to massively accelerate project workflows.

• SAP IS-U transformation project

SAP S4Hana transformation project – focus on Customer Engagement (CE) & MCM

• Customizing tasks & Development tasks
• Master data in Customer Engagement (BP/ Contract Account / Contract / PoD &Supply Scenario)
• Customizing Customer Engagement
• Upil
• BSP / Badi / ABAP OO / ADT / CDS / RAP

• Digital strategy and brand repositioning.
• Website relaunch with UX optimization.
• Digitization of the recruiting process.
• Leadership of cross-functional teams.

• Lead architect for an enterprise loan digitisation programme, coordinating 12 engineers across five workstreams and serving as final technical authority on system design.
• Cut critical application response times by 68% (display 17.3s → 5.6s; modification 11.8s → 5.0s) through targeted caching, OData query optimisation and lazy-loading refactoring; further optimisation in progress.
• Own production error triage, prioritisation and resolution across a multi-application portfolio supporting live lending operations.
• Design and implement SAP Fiori applications on SAP UI5, TypeScript and RAP, owning delivery from architecture and code through rollout and production support.
• Established C4 architecture documentation and decision records for the full programme, enabling faster onboarding and consistent cross-workstream design governance.
• Co-managed S/4HANA release cycle alongside primary responsibilities, coordinating directly with SAP support to resolve critical system issues across the portfolio.

• 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.

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.

• 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

• Developing modern web applications with a focus on React and Next.js

• Building e-commerce and business platforms for SMEs

• Analyzing and optimizing software and data structures

• Planning and developing custom IT solutions

• Structuring data flows and system architectures

• Ongoing project work in web development and platform solutions

• Tax Advisor Platform with Client Portal and Admin System:

• Developing a web-based platform with an integrated client portal

• Building a system consisting of a website, admin area, and client application

• Developing a role-based access system (Admin / Client)

• Implementing document and invoice management

• Digitizing business processes

• Developing high-performance frontend structures

• Integrating APIs and backend logic

• Coffee Business Platform with Admin System:

• Developing a web application for a café with administrative features

• Building internal workflows and user management

• Structuring digital business processes

• Developing modern UI components with a focus on performance

• Shared Account Platform (Admin & Client Applications):

• Developing a scalable platform with separate applications for admins and users

• Building a role-based access system

• Developing a modular frontend architecture with React and TypeScript

• Integrating API structures and data management

• Role: Developer, Architect
• Technologies: java, typescript, golang, spring (boot, web, security, data), Angular, AWS (OpenSearch, Aurora, SNS/SQS, CloudWatch, EC2, IAM), Kubernetes, Terraform, Helm, OAuth, Keycloak, CI/CD, gradlew, Liquibase, Test Driven Development, shell scripting

• Developed backend services with Python
• Data integration and processing of large datasets
• Performance optimization and SQL integration

• My main task was to update and further develop the newly acquired Adesso Sports Platform
• Took over project and team leadership
• Adjusted the cloud infrastructure to reduce costs
• Led the technical takeover of the project
• Trained new employees
• Oversaw and supported mobile development

• Contributed to the development of the Rubix editorial system
• Implemented various microservices based on Java, AWS S3, AWS SQS, AWS SNS, and Spring Boot, deployed to AWS ECS and AWS Fargate
• Designed and developed AWS Lambdas using TypeScript
• Used PostgreSQL in an AWS RDS Aurora cluster and AWS DynamoDB
• Implemented continuous deployment with GitLab pipelines
• Built an Infrastructure as Code environment with AWS CDK
• Set up and maintained a monitoring platform using AWS CloudWatch
• Developed various frontend components with Vue.js
• Designed the microservice architecture applying Domain Driven Design and GraphQL interfaces

• Industry: automotive / banking
• Preparation for SAP HANA implementation
• Conducting HANA readiness check
• Setting up business partner for HANA
• Developing the CONCUR-SAP interface
• Designing and configuring new payment methods
• Upgrading payment transaction formats
• Documentation with JIRA and Confluence