Benjamin Eckstein

The short version

Senior Engineer at Kleinanzeigen by day — building agentic systems on one of Germany's largest platforms. By night, I go wild on side projects and experiments, pushing AI agents to their limits. The best part: the experiments feed back into the real work, and the real work grounds the experiments.

Most AI tutorials stop at ChatGPT prompts. I teach what happens after — agents writing code, running tests, creating PRs, monitoring CI. Not theory. Production reality.

Everything I learn, I share — through blog posts, workshops, and hands-on training. Not to hand out shortcuts, but to connect with others on the same path. We learn faster when we learn together.

Before Kleinanzeigen

Before joining Kleinanzeigen, I spent three years at Novatec Consulting (now part of CGI), working as a senior engineer across multiple enterprise clients. Different tech stacks, different team cultures, different problems — every engagement sharpened how I think about architecture and delivery.

I earned my ISAQB software architecture certification during that time, which formalized what I'd been doing instinctively: designing systems that work at scale and survive real-world complexity. Before Novatec, I co-founded two startups — one processing over 4 million loyalty transactions.

The point isn't the résumé. It's that what I'm doing now with agentic engineering isn't a beginner's experiment. It's built on 20 years of shipping software across consulting, startups, and enterprise — and that foundation is exactly why it works.

What I do at work

At Kleinanzeigen (formerly eBay Kleinanzeigen), I work on one of Germany's largest marketplaces. My day job involves Spring Boot/Kotlin backends, React/Next.js frontends, and a 12-service microservice architecture.

I've built an agentic engineering system with 18 specialized agents that handle everything from Jira ticket analysis through implementation, testing, code review, PR creation, CI monitoring, and Slack notifications. The full pipeline runs autonomously — from ticket to merged PR.

What I do after work

I build things. This website was built in a single session with Cairn — my persistent AI orchestrator. A $187 full-stack cashback app with 729 tests. An OCR receipt scanner that hit 97.78% confidence. Every experiment pushes the boundaries of what's possible with agentic workflows.

332 sessions logged. 5,428 prompts. Every session journaled, every pattern distilled. The blog documents the honest journey — failures included.

Why I share this

AI-assisted development is the biggest shift in how we build software since containers. Most people are still at L0-L1 — using AI as a fancy autocomplete. The gap between that and orchestrating autonomous agent teams is where the real leverage is. I've walked that path and I want to help others walk it faster.