About us

We are a venture-backed startup in stealth, building data infrastructure for the age of AI agents. A small, senior founding team, already working with design partners and early enterprise customers. We value judgment over process and ownership over hand-holding, and we build things that hold up under real load. We will tell you what we are building in conversation, under NDA.

The role

You will own the architecture of the core engine at the heart of our product, hands-on, from the first line of code. This is a principal role that is equal parts research and engineering: many of the hard problems are still open, and your job is to turn them into prototypes, decide with evidence what holds up, and then build production-grade backend systems in Go.
We are an AI-first engineering organisation. Engineers orchestrate coding agents for coding, testing, documentation and operations, and stay fully accountable for the result. You will help set the bar for how that works in the most demanding part of our stack.




You report to our Head of Engineering and will be one of the first principal engineers on the team .

What you bring

Ten or more years building backend systems, several of them at staff or principal level owning the architecture of a core service.

Expert in Go: concurrency, performance profiling, memory behaviour and idiomatic design of large codebases. Strong distributed-systems fundamentals.
Hands-on experience building search, query or data-intensive systems at scale, and a deep understanding of how retrieval works for LLM applications.
Research ability: you can take an open-ended problem from literature review to working prototype to measured result, and you have a track record of original technical work others built on, whether papers, patents, open source or internal systems.
You already orchestrate coding agents as your default way of working, can show concrete examples, and can tell us what you did not trust them with.
Systems thinking, high standa

📌 Principal Engineer. AI-first Engineering (Madrid)
🏢 Stealth Data AI Startup
📍 Madrid