Security Engineer, Offensive Security at Fluidstack in San Francisco, CA

Job description

About Fluidstack We exist to make humanity more free. For most of human history, you farmed or you starved. Technology gave people more time for the things they wanted to do, instead of things they had to do. Powerful AI will be the biggest lever for human choice we've ever built - but only if models are aligned with what humanity actually wants. There are groups building AI who don't share these goals. Whoever deploys frontier compute infrastructure fastest will decide whether AI expands human freedom or shrinks it. We're singularly focused on delivering 10 to 100s of GWs of compute faster than anyone else, rethinking every layer of the stack. We acquire power, design and build data centers, and operate them - with teams spanning hardware and software. Speed and scale are our key differentiators. Come be a part of building civilization-scale infrastructure for AI. We hire people who care deeply about this problem space. If that is you, please apply! How We Operate Be a barrel. Full autonomy. Own things end to end, take on scope without being asked, no permission required to operate outside your core role. Insane urgency. We drive everything forward as fast as possible. Reason from first principles. Challenge every assumption. Zero analogy thinking, no egos, the best idea wins. Love of the game. The frontier of AI is the most interesting problem of our time. We put in long hours at high intensity to push the frontier forward. Build something that actually matters. If you're going to spend your time, spend it on something that matters to the world. The Security Team Examples of key problems the team is working on You're securing the frontier of AI. The model weights training on our infrastructure are the most valuable and most targeted artifacts in technology, and we're standing up the compute to hold them faster than anyone ever has. A breach isn't a leak, it's the frontier walking out the door. Build the entire security program from scratch. Most leaders inherit someone else's system and spend a career patching it. Here you own it end to end, bare metal to boardroom, as we scale across continents. Your threat surface is measured in gigawatts. The customers running on our infrastructure are building the most consequential technology in human history, and being responsible for the physical and logical security of that work makes everything else feel small. Role Scope Run red and purple team operations emulating advanced threat actors across our networks, data center OT, and applications, extending the offensive program alongside the team's other specialists. Pen test the networks behind our GPU clusters, from frontend and backend fabrics to out-of-band management and site connectivity, with a focus on segmentation and tenant isolation. Test data center OT, including building management, power monitoring, cooling controls, and the IT/OT boundary, in partnership with site operations so testing never puts a live site at risk. Break the customer-facing platform, including the console, public APIs, and identity and access controls, hunting for any path from one tenant to another. Assess internal and employee-built applications and the CI/CD pipelines that ship them, and turn recurring findings into secure defaults engineers adopt. Partner with security and engineering teams on AI-specific attack scenarios, including agentic systems and other novel AI-enabled risks, and contribute to AI-assisted offensive testing tools and workflows. Present findings to technical and executive audiences as clear, actionable risk that shapes the security roadmap. What We're Looking For The below is a starting point. We always make space for exceptional people, so if you don't fit this role exactly, tell us where you would . You have years of hands-on experience in red teaming and offensive security operations. You have deep expertise in at least two of: enterprise and data center networks, OT/ICS, web and API applications, cloud (AWS, GCP, Azure), Kub