Founding AI Engineer at Refractal

This is a job that Jill, our AI Recruiter, is recruiting for on behalf of one of our customers. She will pick the best candidates from Jack's network. The next step is to speak to Jack. Job Title Founding AI Engineer Salary Not Disclosed Company Description Refractal is a London-based startup building security infrastructure for autonomy, recognized by MIT’s CSAIL Alliances and selected for Google’s Gemini Cybersecurity Startup Forum. Job Description As a Founding AI Engineer at Refractal, you will build the critical safety layer for agentic systems. You'll own the development of runtime classification stacks, policy engines, and evidence pipelines that secure high-consequence AI deployments for leading startups and government entities. This is a rare opportunity to define a new category in cybersecurity. Location London, UK Why this role is remarkable * Join a powerhouse founding team with technical pedigree from MIT, NASA, Microsoft, and the NSA building at the frontier of AI security. * Work on real-world, high-consequence deployments for a European government and top-tier startups rather than purely synthetic research environments. * Direct path to Head of Engineering with significant founding equity and influence over the product roadmap and research agenda. What You Will Do * Develop the runtime classification stack that authorizes agent actions in real-time, ensuring safety and compliance before execution. * Build high-performance evidence pipelines to record AI verdicts and rationale, providing transparent governance for autonomous systems. * Collaborate with security researchers to translate novel adversarial attacks into robust, production-ready detections and multi-modal controls. The ideal candidate * 0–3 years of experience in AI/ML systems with a strong foundation in computer science, machine learning, or cybersecurity. * A proven builder with a portfolio of production-grade systems, research at top labs, or significant open-source contributions. * Rigorous understanding of how adversaries exploit LLMs and agents, including prompt injection, goal hijacking, and data exfiltration. Who are Jack \& Jill? Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support. And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate. How does this work? * Jack's an AI agent for job searching and career coaching. He works for you. * Jill is the AI recruiter working for the company. She recruits from Jack's network. * If it's a match and the company wants to meet you, they'll make the intro. In the meantime, if you'd like, Jack will send you excellent alternatives. We never post fake jobs This isn't a trick. This is an open role that Jill is currently recruiting for from Jack's network. Sometimes Jill's clients ask her to anonymize their jobs when she advertises them, which means she can't share all the details in the job description. We appreciate this can make them look a bit suspect, but there isn't much we can do about it. Give Jack a spin! You could land this role. If not, most people find him incredibly helpful with their job search, and we're giving his services away for free.