Security Engineer

About us

Security Engineer

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

Our work spans several security domains. You’ll go deep where your strengths and interests are strongest, with opportunities to explore new areas alongside the team.

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. You’ll 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 team to threat model designs, review code and architectures, and implement and evolve Sierra’s security primitives. You’ll 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. You can apply that expertise across unfamiliar systems and emerging threats.

Product and Platform Mindset.

You care about building secure, scalable systems that enable , not block, innovation. You work closely with teams across Sierra to make trade-offs clear and help them move quickly without sacrificing trust.

Software Engineering and Systems Thinking.

You’re comfortable reading and writing code, understanding how production systems fit together, and building pragmatic software solutions to security problems. You can reason about system design and contribute to APIs, services, and security controls, with an eye toward reliability and maintainability.

Curiosity and Ownership.

You take ambiguous, cross-cutting problems from first principles to production and go deep when needed: threat modeling a distributed system, tracing an authorization decision across services, or following an investigation from weak signal to root cause. You define the problem, align partners, build the solution, and own it in 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 — you naturally ask “what could go wrong?” when reviewing designs or investigating systems. You’ve found or fixed real security issues in production.
• You thrive in 0→1 environments , where foundational systems have to balance speed, reliability, and trust.