MTS - Engineering (Security)

Collinear AI, Inc.; San Francisco (CA); On-site; USD 170,000 - 220,000; Full time

Job summary

Collinear AI, Inc. is seeking a senior security-focused engineer to own security across our infrastructure, products, and customer data.

You will work with researchers and engineers to set direction and implement new security measures for RL environments and training data used by frontier AI labs. You will lead critical security initiatives, including cloud security on AWS, defense against adversarial threats, and secure software supply chains, while guiding engineering teams toward safer,

Qualifications

• 8+ years in security engineering, with production cloud experience.
• Deep hands-on AWS security experience: IAM, CloudTrail, GuardDuty, KMS, VPC.
• Offensive security background: pentesting, red team, or vulnerability research.
• Experience isolating workloads with containers or microVMs (gVisor, Firecracker, Kata).
• Production-grade Python code writing; prefer automation.
• Built or grown a security program at a startup; prioritization skills.
• Able to explain risk to engineers, leadership, and customers’ security teams.

Responsibilities

• Harden sandboxes where AI agents run untrusted code.
• Own AWS security design and least-privilege access.
• Build detection and response across cloud and Kubernetes.
• Protect customer data from ingress to delivery.
• Lead customer security reviews and SOC 2 efforts.
• Secure the software supply chain and CI/CD.
• Set guardrails for production infrastructure.
• Test systems like a white-hat attacker and fix issues.

Skills

Security engineering

AWS security

Offensive security

Container isolation

Python programming

Security program leadership

Risk communication

Tools

gVisor

Firecracker

Kata Containers

Job description

About the role

As a Member of Technical Staff - Engineering (Security), you will own security across Collinear's infrastructure, products, and customer data. We build RL environments and training data for frontier AI labs and large enterprises. They trust us with sensitive data and access to their systems, and many of our environments run AI agents that are being trained to find and exploit vulnerabilities.

This is a senior, hands-on role. You will work alongside our researchers and engineering team to set the direction for, and implement, new security measures.

What you'll do

• Harden the sandboxes where AI agents run untrusted code, including cyber tasks where agents are actively trying to break out

• Own AWS security, including IAM design, least-privilege access, network boundaries, and short-lived credentials in place of long‑live keys

• Build detection and response across our cloud and Kubernetes environments, and tune alerts so the team acts on them

• Protect customer data from the moment it arrives to the moment we deliver, including access controls, secure delivery, and PII removal at terabyte scale

• Lead customer security reviews and compliance work, from security questionnaires and supplier onboarding to SOC 2

• Secure our software supply chain, including dependencies, CI/CD, secrets, and our GitHub organization

• Set guardrails for engineers and coding agents that work directly against production infrastructure

• Test our systems the way an attacker would, and fix what you find

About you

• You have 8+ years of experience in security engineering, much of it securing cloud infrastructure in production

• You have deep hands‑on experience with AWS security, including IAM, CloudTrail, GuardDuty, KMS, and VPC design

• You have an offensive security background, such as penetration testing, red teaming, or vulnerability research, and use it to decide what to defend first

• You have isolated untrusted workloads with containers or microVMs, using tools such as gVisor, Firecracker, or Kata Containers, and know where that isolation tends to fail

• You write production-quality code, ideally in Python, and prefer automation to manual process

• You have built or grown a security program at a startup, and know how to prioritize when you can't fix everything at once

• You explain risk clearly to engineers, leadership, and customers' security teams