About

Hi, I’m Ivan Fedyunin, unmanbearpig on GitHub and elsewhere.

Senior software engineer · LLM systems, data pipelines, agent-first development

I’ve been building backends for 15 years. For clients, my AI work has mostly been data: scrapers and LLM pipelines that turn messy documents into searchable data. HostelPunk is where I went deeper, with labeled evals, small models replacing LLM calls, and local inference. Now I want AI to be the main thing I work on.

Since Claude Opus 4.5 came out in November 2025, agents write pretty much all of my code. I learned to make that work on HostelPunk and at Oversize.io. Both needed far more than I could build by hand, so the agents had to work without messing up the codebase and without me checking everything after them. I keep learning which models can do what, which workflows hold up, and how to turn a hard, vague problem into something agents can solve on their own. I hate boring work and agents are great at it, so these days I pretty much only do the fun parts.

I’m a geek and I love computers. Also interested in security, privacy and social aspects of technology.

My professional profile, CV and projects are on ivanfedyunin.com. Email ivan.fedyunin@gmail.com.

My listening stats are here: listenomics.unmb.pw/user/unmanbearpig/charts