Hi!
I'm Marcin — a software engineer with many years of experience in the IT industry. I currently work as a Principal Software Engineer at Allegro, where I design and build fintech systems for one of the largest e-commerce platforms in Europe.
I started my career as a credit risk analyst, then moved through roles such as developer, manager, and tech lead, eventually transitioning into a principal engineer and architect position. I've always been closely connected to the financial domain — core banking systems, general ledgers, as well as scoring and settlement systems are areas I know inside out. More recently, I've been diving into the AI ocean, fishing for promising ideas and testing which ones actually make sense in real-world financial systems.
My superpower: connecting worlds
My career path allows me to look at problems from multiple perspectives at once. I understand business, people, and technology, which means I don't design systems in isolation or purely for slides. I focus on solutions that can be built, maintained, and evolved in real organizations, not just described nicely in documentation.
A good technical solution won't defend itself — if you can't explain it clearly, it will lose anyway. That's why I continuously develop my skills in communication, presentation, and sense-making.
Why this blog?
I don't plan to publish on a regular schedule. This blog exists because from time to time I build or explore something interesting — an experiment, a proof of concept, or an architectural deep dive — and repeating the same story to different people simply doesn't scale.
If there's a new post here, it means I've tested, built, or thought through something deeply enough to believe it's worth writing down. I mostly write about financial system architecture, AI in practice, and how to connect those two worlds in a way that actually makes sense — without hype and without empty theorizing.