About

I’m Jakub Milkiewicz, a software engineer and hands-on architect based between Poznań and Berlin. I’ve been building backend systems for almost 20 years: from banking in Poland, through eBay and SAP, to a long run of Berlin startups and scale-ups.

Some of the things I’ve built along the way:

Workflow orchestration with Temporal: as Tech Lead at Orcrist, a platform that processes customer audio, video, images and chat exports through configurable, LLM-powered pipelines (TypeScript workflows, Python activities).
Real-time bidding: a DSP serving thousands of bids per second at Webtrekk, and later the discovery and architecture of a new RTB platform for a major Polish e-commerce company.
ML-driven products: bandit algorithms optimizing ad revenue at eBay Kleinanzeigen.
Fintech: fully automated loan risk analysis integrated with SCHUFA and decision engines at Lendico.
Data pipelines: streaming and batch on Kafka, Spark, Beam and Debezium.

I mostly work in Kotlin, Java and TypeScript, usually as a hands-on architect who designs the system and writes much of the code. My toolbox includes DDD and Event Storming for modelling, event-driven architecture on Kafka, and TDD plus explicit contracts between services, so that a system stays easy to change long after the first release.
I co-organized GeeCON and was active in the Poznań JUG and Software Craftsmanship Berlin, so sharing what I learn comes naturally. That’s what this blog is for.

Open to new opportunities: Tech Lead / Staff / hands-on architect roles or freelance projects, remote or in Poland/Germany. Especially interested in durable execution, distributed workflows and LLM-based systems.