Full-Stack Engineer

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 Full-Stack Engineer Salary £120k-£130k + Equity Company Description VC-backed AI cybersecurity startup Job Description You will join an early-stage team building an AI-native platform that automates vulnerability management by applying real-world attacker logic. As a full-stack generalist, you'll work across Python and React to build agentic AI systems that investigate security risks, trace root causes, and ship automated guardrails for engineering teams. Location London, UK Why this role is remarkable Join a high-caliber team of four as an early employee with direct founder access and significant product ownership.Work on cutting-edge agentic AI that solves complex cybersecurity problems at a scale humans cannot match manually.Backed by top-tier VCs and industry-leading advisors from global tech giants, operating in a massive $17B+ market. What You Will Do Develop and maintain a Python-based backend and React frontend, ensuring seamless integration of AI-driven security features.Build and optimize evaluation pipelines and agentic AI models that simulate attacker reasoning to identify exploitable vulnerabilities.Collaborate directly with the founder to design, prototype, and ship customer-driven features that bridge the gap between security and development. The ideal candidate Has 4-6 years of professional experience with strong Python fundamentals and a proven track record of shipping production-ready code.Possesses deep applied-AI knowledge, including experience with model trade-offs, evaluation frameworks, and leveraging LLMs as a force multiplier.Thrives in fast-paced startup environments and enjoys solving complex, ambiguous problems across the entire technology stack. 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.