Security Engineer

About Us

Sierra is the leading platform for customer-facing AI agents, working with many of the world's biggest brands — including The GAP, Rocket Mortgage, SoFi, Sutter Health, and SoftBank — to transform how they serve customers and grow their businesses. We are primarily an in-person company based in San Francisco, with growing offices across North America, Europe, and Asia.

Role Overview

Security Engineering builds the foundations that let Sierra deliver powerful AI agents while protecting customer data and trust. We partner across product and platform to make security, privacy, and safety core product capabilities and secure defaults.

What You’ll Do

• Build the Foundations of Trust: Design and ship systems and controls that make Sierra secure by default — spanning product security, infrastructure security, enterprise security, identity, and detection and response. Work across all layers of our platform to identify risk, strengthen architectures, and build durable defenses.
• Own Cross-Cutting Systems: Partner with product, platform, and infrastructure teams to threat model designs, review code and architectures, and implement and evolve Sierra’s security primitives. Make pragmatic design trade-offs between usability, performance, reliability, and security.
• Find and Reduce Real Risk: Identify vulnerabilities, investigate suspicious behavior, and improve detections and response workflows across applications, cloud infrastructure, identity, endpoints, and internal systems. Turn what you learn into systemic fixes and controls that prevent entire classes of issues.
• Automate and Scale Security Workflows: Create developer-friendly tooling to reduce risk and friction — whether through automating security checks in CI/CD, building secure paved paths, improving vulnerability discovery, or instrumenting high-signal detection and response.

What You’ll Bring

• Deep Security Expertise: Strong security fundamentals and depth in at least one domain, such as product security, platform or cloud security, enterprise security, identity, detection and response, or offensive security.
• Product and Platform Mindset: Ability to build secure, scalable systems that enable innovation, working closely across teams to balance trade-offs.
• Software Engineering and Systems Thinking: Comfortable reading and writing code, understanding how production systems fit together, and building pragmatic software solutions. Ability to reason about system design and contribute to APIs, services, and security controls.
• Curiosity and Ownership: Track record of taking ambiguous, cross-cutting problems from first principles to production.

Even Better If…

• You’ve worked across more than one of product security, infrastructure security, enterprise security, detection and response, or offensive security.
• You’ve built security frameworks, platforms, or solutions that engineers and responders rely on to prevent, detect, investigate, and remediate security issues at scale.
• You have exposure to AI systems or care about designing secure-by-default LLM applications and agentic systems.
• You think like an attacker and have found or fixed real security issues in production.
• You thrive in 0→1 environments.