Senior Engineer

Who you are

• 3+ years of experience building and operating production systems
• Hands-on experience in Rust, Python, or Go in a production environment
• Demonstrated ability to optimize networked applications for latency and throughput using profiling and concurrency techniques
• Strong background in security-oriented engineering: threat modeling, vulnerability mitigation, and data integrity in distributed systems
• Track record of comprehensive testing — unit, integration, and failure-scenario coverage — as a normal part of shipping
• Practical fluency with AI coding assistants, with the judgment to critically assess outputs rather than accepting them uncritically
• Experience with authentication standards and protocols such as OAuth, OIDC, or SAML
• Exposure to AI agent systems, agentic frameworks, or machine-to-machine authentication patterns
• Experience working on foundational platform or infrastructure services where correctness is non-negotiable

What the job involves

• Menlo Security is hiring a Senior Software Engineer to own and evolve our Authentication Service — the layer that every user request and AI agent request flows through before anything else happens
• Authentication is foundational to how our browser security product works, which means the decisions made here have direct consequences for security posture, system performance, and how Menlo's platform can grow
• You will work with a team that has deep context on this system, taking full ownership from design through deployment on services that protect enterprise customers at scale
• This role sits at the intersection of systems engineering and security, and it is increasingly central to how Menlo secures AI agent access in enterprise environments — a fast-moving and technically interesting problem space
• Outcomes & KPIs:
• Key Outcome(s) Owned:
• Reliable, secure, and performant authentication services that correctly handle every user and AI agent request flowing through the Menlo platform
• Full lifecycle ownership of assigned services, from design and implementation through deployment and ongoing operation
• Success Metrics / KPIs: (drafted for hiring manager review and adjustment)
• Authentication service availability and latency meeting or exceeding defined SLOs under production load
• Zero critical security vulnerabilities shipped to production in owned code, measured by post-release security review outcomes
• Test coverage and failure-scenario validation maintained or improved across owned code paths
• Features delivered on committed roadmap dates, with defect and rollback rates tracked post-release
• AI agent authentication capabilities shipped in alignment with the Agentic protection roadmap
• What You'll Do:
• Design, build, and own production services in the Authentication Service, with direct responsibility for correctness, scalability, and security from day one
• Develop and extend Menlo's AI agent authentication capabilities, ensuring the platform can securely govern how AI agents authenticate and access enterprise resources
• Optimize for latency and throughput in networked applications, using profiling tools and efficient concurrency models to handle demanding production workloads
• Apply rigorous security engineering practices — including threat modeling and vulnerability mitigation — to protect data integrity across distributed environments
• Use AI coding and debugging tools as part of your development workflow, while critically evaluating outputs for correctness, security implications, and long-term architectural fit before they land in production
• Partner cross-functionally with product, security, and AI engineering teams to ship authentication capabilities end to end
• Write comprehensive unit and integration tests covering failure scenarios, and conduct code and design reviews for peers