Product Engineer
Calibre
<h2><strong>About the job</strong></h2><p style="min-height:1.5em"></p><p style="min-height:1.5em"><strong>About Calibre</strong></p><p style="min-height:1.5em">AI systems are moving from proof of concepts into the infrastructure of everyday life. That creates a fundamental technical problem: how do you know an increasingly autonomous AI system is secure, reliable and behaving as intended? And who do you trust to answer that question?</p><p style="min-height:1.5em">The institutions and processes we rely on to provide that confidence were built for a slower, more predictable world. AI is advancing faster than the mechanisms we use to trust it.</p><p style="min-height:1.5em">Calibre is building trust for the AI era as the first AI-native certification body. We develop core technologies to understand AI and cybersecurity risk, and use them to independently assess companies against leading standards.</p><p style="min-height:1.5em">Founded by two ex-Palantir technical co-founders, and a founding team spanning audit and AI research, we are pushing the frontier of what trust looks like for the AI economy. We’ve raised $3.3M<strong> </strong>from top tier SF based VCs.</p><div style="min-height:1.2em;margin-top:0;margin-bottom:0"> </div><p style="min-height:1.5em"><strong>The Role</strong></p><p style="min-height:1.5em">We are hiring a <strong>genuinely exceptional</strong> Product Engineer to join the founding team and build a new class of products to supercharge our AI-native certification process.</p><div style="min-height:1.2em;margin-top:0;margin-bottom:0"> </div><p style="min-height:1.5em">This person is language-agnostic, obsesses over first principles, and has already integrated LLMs into their daily workflow as a true force multiplier.</p><div style="min-height:1.2em;margin-top:0;margin-bottom:0"> </div><p style="min-height:1.5em"><strong>What You Will Do</strong></p><ul style="min-height:1.5em"><li><p style="min-height:1.5em"><strong>Own products across the whole stack. </strong>Build and ship high-quality, high-velocity code across the full stack (front-end, back-end, and AI-agent infrastructure)</p></li><li><p style="min-height:1.5em"><strong>Build products end-to-end. Design systems from discovery through to production.</strong></p></li><li><p style="min-height:1.5em"><strong>Engineer reliable agent systems. </strong>Design harnesses, evals and safeguards that make quality non-compromisable.</p></li></ul><div style="min-height:1.2em;margin-top:0;margin-bottom:0"> </div><p style="min-height:1.5em"><strong>What we’re looking for</strong></p><ul style="min-height:1.5em"><li><p style="min-height:1.5em"><strong>Demonstrable AI engineering depth. </strong>You can show real systems where you made substantive decisions about agent harnesses, evals, hallucination containment, performance, agent sandboxing or MCP/tool design.</p></li><li><p style="min-height:1.5em"><strong>Strong product engineering and technical judgment. </strong>You ship across interface, backend, data and deployment, reason from first principles and choose tools deliberately.</p></li><li><p style="min-height:1.5em"><strong>Product instinct and clear collaboration. </strong>You ask good questions, form a view, test quickly, communicate clearly and care whether the work changes outcomes.</p></li><li><p style="min-height:1.5em"><strong>Evidence of exceptional output. </strong>Show us professional work, open-source contributions, personal products, research or hackathon results. Roughly 2+ years of experience is useful, but evidence matters more than tenure.</p></li></ul><div style="min-height:1.2em;margin-top:0;margin-bottom:0"> </div><p style="min-height:1.5em"><strong>The Ideal Candidate</strong></p><ul style="min-height:1.5em"><li><p style="min-height:1.5em"><strong>Exceptional technical talent</strong> with more than 1 year of professional experience. Your GitHub, personal projects, or hackathon wins speak for themselves.</p></li><li><p style="min-height:1.5em">A <strong>first-principles problem solver.</strong> You have a fundamentally strong computer science background (e.g., from a top university or equivalent experience) and are language-agnostic, picking the right tool for the job.</p></li><li><p style="min-height:1.5em"><strong>AI-Native:</strong> You are already a sophisticated user of LLM tools (e.g., Claude Code, Cursor, etc.) for coding. You understand their strengths, weaknesses, and how to build systems that leverage them effectively.</p></li><li><p style="min-height:1.5em"><strong>High-Leverage & High-Output:</strong> You thrive in a high-pressure, high-growth environment. You understand that in an early-stage startup, precision and speed are paramount.</p></li></ul><div style="min-height:1.2em;margin-top:0;margin-bottom:0"> </div><hr><p>Compensation: £60K – £150K • 0.25% – 1%</p><ul><li> • £60K – £150K • 0.25% – 1%</li></ul><p>Find more <a href="https://www.arbeitnow.co.uk/english-speaking-jobs">English Speaking Jobs in United Kingdom</a> on Arbeitnow</a>