Founding Security Engineer

About the job MeeBoss is sharing this active opportunity on behalf of the hiring company. This is a founding security role at a Sequoia-backed Series B company that has grown 20x year-over-year in revenue. The position involves building the entire security program from scratch with greenfield ownership and direct reporting to the co-founder/CTO. The company works with elite engineering teams and serves world-class customers including Anthropic, Google, Microsoft, and Robinhood. Job title Security Engineer Company MeeBoss Location San Francisco, CA (On-site) Why this role Founding security role with real impact at a high-growth company.Direct report to the CTO with high visibility and autonomy.Opportunity to build out a team and deepen scope as the company scales. What you will do Define and build the security architecture from the ground up across the LLM pipeline, infrastructure, and product.Take ownership of the entire security program as the first dedicated security hire.Work closely with engineering pods to identify vulnerabilities, run threat modeling, and ensure secure design patterns.Harden multi-tenant isolation and collaborate with the infrastructure team on multi-region data residency.Manage pen tests, vulnerability scans, and write lightweight policies to maintain compliance and security.Own internal IT, including devices, access, and identity.Serve as the technical ground truth behind audits, questionnaires, and enterprise security reviews.Contribute to and help evolve the security roadmap as the company scales with Fortune 500 customers. What we are looking for 7 to 15 years of experience in security engineering or software engineering transitioning to security.Hands-on experience spanning application security and infrastructure security.Proven track record of building a security program from scratch.Expertise in threat modeling and vulnerability assessment, including pen tests, vulnerability scans, and risk prioritization.Ability to read and review code for security vulnerabilities (not purely GRC/compliance).Experience in cloud security architecture and multi-tenant isolation. About MeeBoss MeeBoss helps job seekers and hiring teams make direct, relevant career connections.