Senior Engineer I (Auth)

Job description

Menlo Security is the leader in Browser Security for human and agentic workforces. Our mission is to enable humans and agents to connect, communicate, and collaborate securely, without compromise. The Menlo Browser Security Platform protects organizations from cyberattacks by stopping threats across the web, documents, and email before they reach the user. With Menlo Agent Runtime Security (MARS), that protection now extends to the AI agents working alongside every employee. Menlo Security is trusted by major global businesses, including Fortune 500 companies and government agencies, to protect their most valuable asset, their data, and is backed by top-tier investors. SUMMARY 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. FUNCTIONAL COMPETENCIES Required: - 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. Preferred / Nice to Have: - 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. Our Compensation and Benefits At Menlo Security, Base Salary is one part of our competitive total compensation and benefits package and is determined using a salary range. The base salary range for this role is 112,000 CAD - 168,000 CAD. In accordance with Canadian law, the range provided is Menlo Security’s reasonable estimate of the base compensation for this role. The actual amount may be higher or lower, based on non-discriminatory factors such as experience, knowledge, skills, abilities, and location. All employees may be eligible to become Menlo Security shareholders through eligibility for stock-based compensation grants, which are awarded to employees based on company and individual performance. Menlo Security does not accept unsolicited resumes from search firm recruiters. Fees will not be paid in the event a candidate submitted by a recruiter without an agreement in place is hired; such resumes will be deemed the sole property of Menlo Security. Menlo Security is an equal opportunity employer. All aspects of employment will be based on merit, competence, performance, and business needs. We do not discriminate on the basis of race, color, religion, marital status, age, national origin, ancestry, physical or mental disability, medical condition, pregnancy, genetic information, gender, sexual orientation, gender identity or expression, veteran status, or any other status protected under federal, state, or local law. MSGL-I4 Follow us on LinkedIn https://www.linkedin.com/company/menlo-security/! Why Menlo? At Menlo, we don't settle for the status quo — in our technology or our culture. How we think and act is just as important as what we build. Our culture is defined by five core mindsets: Proactive Leadership, Straight Talk, United Impact, Elevated Talent, and Customer-Compelled. We take ownership and drive outcomes without waiting to be told. We communicate directly and seek hard truths. We break down silos and win together. We hold a high bar for ourselves and the people around us. And we treat every customer interaction as mission-critical. If you're someone who sees it, owns it, solves it, and does it — you'll thrive here. All qualified applicants will receive consideration for employment without regard to race, sex, color, religion, sexual orientation, gender identity, national origin, protected veteran status, or on the basis of disability. TO ALL AGENCIES: Please, no phone calls or emails to any employee of Menlo Security outside of the Talent organization. Menlo Security’s policy is to only accept resumes from agencies via Ashby (ATS). Agencies must have a valid services agreement executed and must have been assigned by the Talent team to a specific requisition. Any resume submitted outside of this process will be deemed the sole property of Menlo Security. In the event a candidate submitted outside of this policy is hired, no fee or payment will be paid.