Software Engineer und Tech Lead

Hive is a logistics and fulfillment company that handles and streamlines e-commerce operations for online brands. I joined them during a phase of very strong growth and worked in the team responsible for the integration of shop platforms and ERPs. The main challenges were scaling up all relevant systems and also adjusting the connectors for new clients in a timely yet thorough fashion. Some of my tasks included:

• Implement, improve and scale integrations for various ERPs and shop systems (Shopify, Xentral etc.)
• Refactor and scale background workers (Sidekiq) for higher throughput and better error resilience
• Shape abstract shop integration for better maintainability and easier addition of future integrations
• Improve observability with structured and centralized logging (AWS Cloudwatch Logs)

Tech: Ruby, Rails, Postgres, Sidekiq, AWS, Docker, Github Actions, Terraform, Grafana

MeinWunschcatering is a marketplace that connects individuals and companies seeking a professional catering with several hundred catering partners throughout three European countries. I led a small team of three developers responsible for the online shop, partner backend and several internal tools. Some tasks and accomplishments include:

• Complete migration of the infrastructure to a new AWS stack
• Setup of automated build pipeline to make releasing smooth and easy for the dev team
• Full rewrite of the partner backend from scratch, and addition of critical features
• Massive reduction of technical debt throughout the app to improve team velocity

Tech: Ruby, Rails, Javascript, Node.js, Vue.js, Postgres, AWS, Docker, Kubernetes

Zinsbaustein is a crowdfunding platform for real estate projects in a quickly growing market. As interim technical lead, I oversaw and was responsible for all software development (frontend and backend) and technical operation of the platform. In this role, I also collaborated closely with the product manager, designer, and other stakeholders. Tasks included:

• Full stack maintenance and feature development for a Rails-based monolith
• Refactoring in preparation for a more scalable and maintainable distributed architecture
• Supporting product manager with technical planning (user stories, roadmaps)
• Setup of build pipeline with CircleCI, including continuous deploys
• Screening, interviewing, and evaluation of new candidates

Tech: Ruby, Rails, Javascript, AWS, Postgres

HERE offers fresh maps and location experiences across multiple screens and operating systems. As part of the innovation team, I contributed to the backend services to provide personalized maps to the users. This involved adding new features as well as stabilizing and consolidating prototypes for product release. The main challenges were scaling the backend and making the location-based data contextually relevant to users.

• Continuous prototyping and improvement of location services along with the mobile apps development team and designers
• Profiling, optimizing, and scaling of the globally distributed Node.js based backend
• Design and implementation of several REST APIs as well as an Angular.js based admin interface

Trademob is a demand-side platform (DSP) for programmatic buying of advertisement. The company grew significantly from small start-up to one of the largest DSP's in Germany during the time of my two projects. This brought a host of challenges for the entire IT team. I worked as a server-side software engineer on large parts of the technology stack, mostly in Node.js and Rails. Many of the challenges in this project concerned scalability, performance, and availability of the involved systems.

• Continuous development, optimization, and scaling of the Node.js-based bidding system that receives about 1.5 billion requests per day (50k requests / second at peaks)
• Development and maintenance of various downstream services for processing and matching of the incoming data (Node.js, Ruby, Cassandra, Redis)
• Integration for the internal Rails-based campaign management dashboard
• Configuration management with Chef, build automation with Jenkins
• Leveraging the AWS cloud infrastructure (EC2, S3, Elasticache etc.)