Software Developer in Friedberg, Germany

I helped to coordinate, design and implement critical parts of the online transaction processing of the Payback platform. Payback is a leading German bonus system with more than 30 million active users across the country.

I co-founded and developed a nice and smart solution to protect Internet users against spam. It was a lot of fun. We had hundreds of active users in the friends and family phase, but the company failed to find an investor (it was during the crisis of 2008). But I am still proud of the software. I handled the development of browser plugins for IE and Firefox.

I designed and led the development of a software suite providing framework and libraries necessary to implement loyalty management programs later used to power international bonus systems (e.g., Lufthansa Miles & More).

I designed and implemented core services for a warehouse management system used in the biggest European warehouses (e.g., Adidas, Nestle, Transpharm, E.Leclerc, and Delhaize). I designed and implemented messaging architecture (100+ requests/second, latency < 60ms); redesigned a build pipeline for software with over 2 million lines of code; inspired, designed, and implemented an API for building complex warehouse layouts; and designed and developed an efficient Java NIO-based implementation of a binary protocol used to communicate with PLCs.

I co-founded and developed an e-procurement platform in Ukraine (1,000+ users), set up the engineering team, and led the development and operation of the platform. The platform implemented different bidding strategies and was highly concurrent.

Autoscout24 is Europe's leading online marketplace for new and used cars, bikes, and trucks. As a lead software engineer, I helped with the migration of an old .NET monolithic app to a cloud and Java stack. I developed and operated important parts of the platform (1+ million requests/min); coached and trained team members; pioneered and evangelised reactive streams; inspired, promoted, and developed a stream-based architecture for data propagation across multiple services; and evangelized functional, reactive, and type-driven development.

Set up an engineering team to develop an online B2B platform for public sector financing in Europe, led the development of the platform, introduced and set up cloud-based infrastructure, set up continuous delivery pipelines, and set up and coordinated the agile development process (Kanban, trunk-based development, and feature toggles).

As a senior software engineer, I led the development of a document management system for a German medical government institution, captured the requirements, prepared user stories, and designed and helped implement the features. The system was intended for internal use (200+ users) for clerks and call center employees.

Designed the architecture and implementation scenario for the migration of old client-server desktop-based mammography software to a software as a service platform. Implemented the prototype to demonstrate the main cornerstones of the new architecture. The software had to display and transform high-quality DICOM images in a browser.

As a senior software engineer, I participated in the design and development of a GMX photo album (10,000+ users), an online photo management application for Germany's biggest email provider, GMX Mail. The application supported uploading, storage, transformation, and displaying images of different sizes and formats.