Senior AI Security Engineer - LLM/Agentic - Remote

Affirm; Boston (MA); On-site; USD 204,000 - 264,000; Full time

Benefits offered by this job

100% subsidized medical coverage

Tech stipends

Flexible time off

Employee stock purchase plan

Job summary

Affirm is seeking a senior security engineer to build and run end-to-end security reviews for enterprise AI/LLM systems, collaborating with Security, Legal, Privacy, Compliance, IT, and Engineering to enable safe AI adoption.

You will design controls, guardrails, and policy-as-code, and lead threat modeling, secure tool-calling frameworks, and cross-functional security initiatives in a remote-first environment.

Qualifications

• Seasoned security engineer with hands-on AI/LLM security design experience.
• Experience threat modeling and securing agent-based systems and tool-calling frameworks.
• Experience in regulated environments (SOC 2, PCI DSS) and IAM for non-human identities is a plus.

Responsibilities

• Lead and continually improve Affirm's enterprise AI security review process for architecture, data flows, permissions, and design of internal AI tools and MCP-based systems.
• Threat model AI/LLM-based systems and data flows for risks and drive remediation.
• Review source code, system prompts, agent configurations, and tool/permission manifests; help tool owners build security-focused test cases and red-team scenarios.
• Design and build security guardrails and tooling for AI systems permission boundaries, authn/authz for agentic tools and MCP servers, data-handling controls, logging/monitoring, and policy-as-code (Python, IaC).
• Evaluate AI capabilities of third-party SaaS vendors as part of vendor security reviews and drive risk-based adoption decisions.
• Identify emerging AI/agentic vulnerabilities and contribute to incident response playbooks as a senior escalation point.
• Lead cross-functional AI security initiatives and stay current on AI security landscape to translate research into practical controls.

Skills

Security architecture

Threat modeling

AI/LLM security

Python tooling

Cloud (AWS)

Kubernetes

OAuth2/SAML

Cross-functional leadership

Regulated environments

Tools

Terraform

Infrastructure as Code

IAM & Okta

GitHub

Job description

Affirm is seeking a senior security engineer to build and run end-to-end security reviews for enterprise AI/LLM systems, collaborating with Security, Legal, Privacy, Compliance, IT, and Engineering to enable safe AI adoption.

You will design controls, guardrails, and policy-as-code, and lead threat modeling, secure tool-calling frameworks, and cross-functional security initiatives in a remote-first environment.