Staff Security Engineer - AI Security & Platforms

Staff Security Engineer - AI Security & Platforms Location: San Ramon, CA; Reno, NV About Ridgeline Ridgeline is the industry cloud platform for investment management. It was founded by visionary tech entrepreneur Dave Duffield (co-founder of both PeopleSoft and Workday) to apply his successful formula of solving operational business challenges with bold innovation and human connectivity to the unique needs of the investment management industry. Ridgeline started with a clean sheet of paper and a deep bench of experts bound by a set of core values and motivated to revolutionize an industry underserved by its current tech offerings. We are building a new, modern platform in the public cloud, purpose-built for the investment management industry and we are prioritizing security, agility, and usability to empower business like never before. With a growing campus in Reno and offices in New York, Lake Tahoe, and the Bay Area, Ridgeline is proud to have built a fast-growing, people-first company that has been recognized by Fast Company as a "Best Workplace for Innovators," by The Software Report as a "Top 100 Software Company," and by Forbes as one of "America's Best Startup Employers." The Opportunity Are you a security engineer who wants to define what secure AI looks like for an entire company rather than chase it after the fact? Do you want to build the platforms and guardrails that let a business adopt AI quickly and safely, while keeping pace with emerging AI threats and how to defend against them? Are you already fluent with AI and treat it as core to how you build? If so, we're standing up a new team and we invite you to help shape it. Ridgeline is building a new AI Security & Platforms team focused on secure AI enablement for the business: building the platforms that support safe AI adoption, and keeping current with how AI is used, the security issues that emerge, and how to prevent them. As a Staff AI Security Engineer, you will own this space at a technical-leadership level. You will architect secure-by-default AI platforms, lead on AI/LLM threat security, partner with teams to embed security into how they build and use AI, and enforce the organization's standards for responsible, secure AI use. Because the domain is still young, we are looking for someone who has already shown strong skills in application security, cloud security, or security-focused software development, and who pairs that with real depth in AI. At Ridgeline, the workplace culture is just as important as the products we build. We value ownership, transparency, and a bias toward action - which means we're always looking for solutions rather than just identifying problems. We're a team that chooses growth over comfort, owns our setbacks as much as our wins, and thrives on the kind of collaboration that pushes everyone to do their best work. If that's the environment where you do your best work, we would be interested to meet you. You must be work authorized in the United States without the need for employer sponsorship. The impact you will have: Architect and build the platforms, guardrails, and reusable frameworks that let Ridgeline adopt AI safely at scale, driving secure-by-default patterns that close entire risk classes before systems are built. Find and mitigate the AI-specific risks that generic tooling misses: prompt injection, model input/output sanitization, data leakage, and trust-boundary violations across AI-powered features and agents. Secure agentic and tool-use systems, including function/tool calling and MCP server integrations, with clear trust boundaries and least-privilege patterns for AI agents. Establish and operate guardrails for internal AI developer tooling (e.g., Claude Code, Cursor, etc.) that let engineering move fast without sacrificing security. Threat model new AI features and infrastructure to define security requirements before they are built, partnering with engineering and product teams so the secure path is also the eas…