Principal Quality Engineer, Quality Agents and VerificationAbout usWe 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 roleYou will own how we know our product is right. This is a principal, hands-on role building the quality layer of an AI-first engineering organisation: the quality agents that test, review and challenge every change, the harness that makes those agents trustworthy, and the shared workflows that put them in every engineer's path from first commit to release. The goal is enterprise-grade quality delivered at the speed agents make possible.
We are an AI-first engineering organisation. Engineers orchestrate coding agents for coding, testing, documentation and operations, and stay fully accountable for the result. When code is cheap to generate,



verification becomes the constraint. Your job is to make verification fast, rigorous and built into how we work, so that we ship to enterprise customers with evidence rather than hope.
You report to our Head of Engineering and will be the first quality engineer on the team, setting the bar for how quality works across the whole stack.
What you will do• Build quality agents. Design agents that generate and extend test suites, review pull requests against our quality bar, run exploratory and adversarial testing, triage failures and flaky tests, and check data correctness in our pipelines.
• Build the harness they run in. Sandboxed environments with scoped credentials, deterministic fixtures and test data, golden datasets, and evaluation suites that measure whether each quality agent finds real defects, how often it raises false alarms, and what it costs per run.
• Design the oracles. Agen

📌 Principal Software Quality Assurance Engineer (Madrid)
🏢 Stealth Data AI Startup
📍 Madrid