- 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- Hands-on experience in Rust, Python, or Go in a production setting

- Practical fluency with AI coding assistants, with the judgment to critically assess outputs rather than accepting them uncritically

- Strong background in security-oriented engineering: threat modeling, vulnerability mitigation, and data integrity in distributed systems

- Demonstrated ability to optimize networked applications for latency and throughput using profiling and concurrency techniques

- 3+ years of experience building and operating production systems

- Track record of comprehensive testing — unit, integration, and failure-scenario coverage — as a normal part of shipping

- Experience with authentication standards and protocols such as OAuth, OIDC, or SAML

- Experience working on foundational platform or infrastructure services where correctness is non-negotiable

- Exposure to AI agent systems, agentic frameworks, or machine-to-machine authentication patterns

📌 Senior Engineer (Authentication) (Canada)
🏢 Menlo Security
📍 Canada