MTS - Engineering (Security)

Collinear AI, Inc.; San Francisco (CA); On-site; USD 140,000 - 200,000; Full time

Job summary

Collinear AI, Inc. is seeking a senior security engineer to own security across infrastructure, products, and data for frontier AI labs and customer environments.

You will harden sandboxes and manage AWS security while collaborating with researchers and engineers to implement new protections. This hands-on role emphasizes building detection, safeguarding customer data, and leading security reviews including SOC 2 readiness.

Qualifications

• 8+ years of security engineering experience, with production cloud security.
• Hands-on AWS security experience: IAM, CloudTrail, GuardDuty, KMS, and VPC design.
• Offensive security background: penetration testing, red teaming, or vulnerability research.

Responsibilities

• Harden sandboxes where AI agents run untrusted code.
• Own AWS security, including IAM design, least-privilege access, and short-lived credentials.
• Build detection and response across cloud and Kubernetes environments and tune alerts.
• Protect customer data from intake to delivery, including access controls and PII removal at scale.
• Lead customer security reviews and SOC 2 readiness tasks.
• Secure software supply chain: dependencies, CI/CD, secrets, and GitHub org.
• Set guardrails for engineers and coding agents working against production infrastructure.
• Test systems the way attackers would and fix findings.

Skills

Security engineering

Cloud security

Python

Tools

IAM (AWS)

CloudTrail

GuardDuty

KMS

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-lived 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