Developer from Potsdam, Germany.

I am passionate about building the best products and making real impact by solving hard problems and delivering shareholder value.

Currently I work on Datadog Test Optimization product that makes your tests go brr 🏎️

Writing

• How we built a Ruby library that saves 50% in testing time @ Datadog

What I worked on

• Test Better, Build Better: The Betterment Approach - how Betterment tamed their CI using Datadog Test Optimization and the client library I built
• Adventures in garbage collection - how we chased down the issue that destroyed our p99 latency at Shopify

Where I worked

• 🐶 Datadog: I created Ruby library for Datadog Test Optimization product (datadog-ci). It helps people to take their CI time from 40 minutes to 9, lift success rates from <50% to 95.4%, reduce the number of flaky tests from 3-digits-number to almost 0, and cut compute spend in half. For this library I created extremely low overhead test impact analysis tool that enables selective test runner that deterministically skips irrelevant tests. I've also written about test impact analysis in Ruby in depth.
• 🛍️ Shopify: I led a team of 3 backend developers to build order management functionality for the Shopify Bundles app. We released the app in public beta and it is expected to be used by thousands of merchants. I also performed a deep dive on performance issues and discovered a garbage collection problem in the main Ruby on Rails monolith that powers Shopify.
• 🚗 SHARE NOW: During the COVID-19 lockdown, I helped our engineering organization to mature and invest in building a competitive advantage for the future post-pandemic. I implemented a dynamic pricing system that increased fleet utilization by 20%, resulting in a 10% increase in profits over the holiday season. I also ensured the internal systems powering SHARE NOW were robust by rewriting the Vehicle Location Tracker, improving its maintainability and resilience.
• 🏗️ kloeckner-i: I built Part Manager e-commerce app, which allowed clients to manage their steel contracts online. By utilizing the tools for concurrent data import provided by the Elixir language, I achieved a 6x increase in data import speed.