Security Foundations Engineer — Crypto & Zero-Trust

Anthropic Limited; San Francisco (CA); Hybrid; USD 320,000 - 485,000; Full time

Job summary

Anthropic Limited, based in San Francisco, CA, is seeking a Security Engineer to design, build and run security foundations across Anthropic's fleet, from threat modeling through production and on-call support. Much of the work is greenfield, offering an opportunity to shape architecture rather than inherit it.

You will focus on cryptographic frameworks, mTLS, and authorization systems while partnering with product, research, infrastructure and other security teams, and you will mentor engineers

Qualifications

• 8+ years of software engineering experience building security-relevant systems in production.
• Strong programming skills in Go, Rust or Python.
• Deep understanding of authentication and authorization systems: OAuth 2.0 / OIDC, JWTs.
• Hands-on experience with PKI, X.509, mTLS and workload identity.
• Experience shipping and operating high-reliability services on Kubernetes across cloud and on-prem environments.
• Ability to own ambiguous technical problems and drive them to resolution across teams.

Responsibilities

• Build critical security foundations including cryptographic frameworks, mTLS infrastructure, secure serialization, and authorization systems, designed to prevent entire classes of vulnerabilities
• Partner with product, research, infrastructure, and other security teams to ensure frameworks integrate smoothly with lower-layer security controls
• Scope, design and build security services and libraries end-to-end, maintain them in production, and drive through ambiguous technical problems with minimal oversight
• Build and operate the zero-trust access gateway that fronts Anthropic's internal services
• Design and roll out authorization frameworks so services enforce least privilege consistently instead of each inventing its own access controls
• Own cryptographic frameworks and libraries
• Mentor engineers, contribute to hiring, and grow security engineering culture across Anthropic

Skills

Go

Rust

Python

OAuth 2.0 / OIDC

JWTs

Kubernetes

PKI / X.509 / mTLS

Threat modeling

Security engineering

Communication skills

Mentoring

Education

Bachelor's degree

Job description

Anthropic Limited, based in San Francisco, CA, is seeking a Security Engineer to design, build and run security foundations across Anthropic's fleet, from threat modeling through production and on-call support. Much of the work is greenfield, offering an opportunity to shape architecture rather than inherit it.

You will focus on cryptographic frameworks, mTLS, and authorization systems while partnering with product, research, infrastructure and other security teams, and you will mentor engineers