Senior Product Security Engineer

Lambda, The Superintelligence Cloud, is a leader in AI cloud infrastructure serving tens of thousands of customers. Our customers range from AI researchers to enterprises and hyperscalers. Lambda's mission is to make compute as ubiquitous as electricity and give everyone the power of superintelligence. One person, one GPU. If you'd like to build the world's best AI cloud, join us. *Note: This position requires presence in our San Francisco or Bellevue office location 4 days per week; Lambda’s designated work from home day is currently Tuesday. About the Role Lambda Security protects some of the world's most valuable digital assets: training data, model weights representing immense computational investments, and the sensitive inputs required to leverage best-of-breed AI models. We're responsible for securing every byte that powers breakthrough artificial intelligence. As a Senior Security Engineer on Product Security, you'll make sure the right security decisions get made in everything Lambda sells, from the network and cluster infrastructure in our data centers to the software our customers use every day. Reporting to the Senior Manager of Security, you'll join a team spanning infrastructure security and application security, owning security outcomes for your area and partnering closely with Product Engineering, Data Center Operations and Engineering, Detection & Response, and GRC. Product security at Lambda generates and protects revenue. Enterprises and AI labs evaluate our security before they move billion-dollar training runs and irreplaceable model weights onto our infrastructure, and this team supplies the answers. As Lambda launches new products and expands into new data centers, you'll threat model and review the designs behind each one, keep every customer's workloads isolated from the network fabric up, run vulnerability management as a risk-driven program, and bring technical depth to the customer security reviews behind enterprise deals. You'll work with direct access to LLMs hosted on Lambda's own infrastructure, alongside frontier models and AI tools, to take code and design review further than traditional approaches allow. Product security covers a lot of ground, and we don't expect one person to be an expert in all of it. Some of our team go deep on infrastructure: networks, clusters, Linux and the hardware underneath. Others go deep on application security and code. We expect you to bring real depth in one and contribute across both. If you'd rather build security into systems alongside the engineers who own them than audit them from the outside, we'd love to talk. We value diverse backgrounds, experiences, and skills, and we are excited to hear from candidates who can bring unique perspectives to our team. If you do not exactly meet this description but believe you may be a good fit, please still apply and help us understand your readiness for this role. Your application is not a waste of our time. What You'll Do - Review Designs and Threat Model: Own security design reviews and threat models for the systems in your area, delivering actionable recommendations while changes are still cheap. - Secure Multi-Tenant Infrastructure: Harden the network, cluster, and infrastructure-service layers that keep each customer's workloads isolated from every other customer's. - Find and Fix Vulnerabilities in Code: Review application code and infrastructure as code, find vulnerabilities through analysis and testing, and land fixes with the owning team. - Run Vulnerability Management as a Program: Turn scanner output into accurate, prioritized facts about real risk, and drive remediation to SLA alongside our Technical Program Managers. - Develop Security Patterns and Requirements: Turn recurring review findings into requirements, reference patterns, and guardrails that the teams you support adopt by default. - Enable Enterprise Deals: Partner with GRC on customer security reviews and architecture discussions, giving customers clear, technically grounded answers about how we protect their workloads. - Build Security Tooling: Ship Python or Go automation, using Lambda-hosted LLMs, frontier models, and AI tools, that extends review and triage coverage. - Partner Across Engineering: Work with Product Engineering, Data Center Operations and Engineering, and Detection & Response, including on bug bounty and vulnerability disclosure reports. - Coach Engineers: Help engineers in the teams you support build secure design instincts, and mentor newer members of the security team. - Balance Strategic and Tactical: Recognize when to invest in a long-term fix versus when "good enough" is exactly that, and bias toward measurable forward progress. You - 5+ years of demonstrated security engineering experience, either directly as a security engineer or as a software, infrastructure, or site reliability engineer driving security outcomes. We also welcome equivalent backgrounds: significant formal security training paired with strong engineering experience. - Demonstrated depth in infrastructure security or application security, with design reviews, threat models, or fixes that engineering teams actually adopted. - A track record of independently owning security work end to end, making sound calls on your own and knowing when to escalate. - Thrives in high-speed, high-ambiguity startup environments where priorities shift regularly and structure must be built while executing. - Strong hands-on Linux experience in both bare metal and cloud environments, understanding infrastructure from kernel to application layer. - Reads application code and infrastructure as code (e.g., Terraform, Ansible, Kubernetes manifests) fluently enough to explain a vulnerability's root cause, not just a scanner's verdict. - Ships production-grade tooling in Python, Go, or a similar language, rather than only one-off scripts. - Translates security risk into business impact for engineers, leadership, and customer