Founding Engineer (£90k-£150k + Equity) at well-funded AI defense startup

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 Engineer Salary £90,000–£150,000 + Equity Company Description Well-funded AI defense startup Job Description You will architect and build a novel multi-agent modeling platform from the ground up to simulate synthetic societies. By leveraging Large Behavioral Models and LLMs, you will create tools that help democratic governments understand and counter information warfare. This is a high-impact, founding-level role focused on the intersection of AI, behavioral science, and national security. Location London, UK Why this role is remarkable * Opportunity to build a complex simulation platform from first principles at the intersection of AI and cognitive security. * Well-funded pre-seed stage with backing from top-tier investors specializing in defense and AI technology. * Direct influence on the technical direction and culture as one of the first engineering hires in the company. What You Will Do * Design and implement the core architecture for a large-scale multi-agent simulation system. * Integrate LLMs and behavioral science models to simulate human responses to information manipulation. * Collaborate closely with the founding team to translate complex security requirements into scalable technical solutions. The ideal candidate * Proven experience building complex, distributed systems or multi-agent simulations from scratch. * Strong background in AI/ML, particularly with LLMs, and a deep understanding of software architecture. * Must be eligible for UK security clearance and comfortable working in a high-ownership startup environment. \=\=\= 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.