About the role

WHAT MATX IS BUILDING MatX is on a mission to be the compute platform for AGI. We are developing vertically integrated full-stack solutions from silicon to systems, including hardware and software, to train and run the largest ML workloads for AGI. MatX is seeking a Senior Security Engineer to join our team as we create best-in-class silicon for high-performance and sustainable GenAI. The successful candidate for this role will be responsible for securing the software, build systems, and cloud infrastructure that MatX products are designed, verified, and delivered on. As a Security Engineer reporting to our Security Lead, you'll work across a stack that spans RTL design flows, compilers and kernels, ML training infrastructure, and the cloud environments that host all of it. This is a generalist role by design. We are a startup, and we would rather hire one engineer who can move between breaking things, reviewing code, and hardening infrastructure than three specialists who each own a slice. Your week might include a threat model with the compiler team, an adversarial look at an internal service, and a redesign of how our build artifacts get signed. Two areas in particular are where we want this hire to push us further than we are today: supply chain and build integrity, and bringing a real attacker's perspective to systems we have so far only reviewed defensively. You'll set direction rather than inherit a playbook, and you'll see the impact of your work quickly. WHAT YOU'LL DO HERE - Own and grow our supply chain and build integrity program - dependency and third-party IP provenance, artifact signing and code signing infrastructure, SBOM generation and consumption, reproducible builds, and hardening of CI/CD systems, build caches, and build runners. This is a priority area for us and the part of the role with the most room to define itself - Bring an adversarial perspective to our own systems: hands-on security assessment of our code and build tooling, internal services and dashboards, developer platforms, and the systems that hold our design data - including manual code review, application and API testing, and assessment of the infrastructure behind them - Conduct vulnerability research against the systems we build and depend on, and turn what you find into fixes and durable controls - Partner with software, compiler, ML, and silicon teams on threat modeling and design review for new systems, and translate the results into concrete engineering work rather than a list of findings - Harden our cloud infrastructure: identity and access management, network segmentation, secrets management, workload identity, infrastructure-as-code review, and guardrails that make the secure path the default path - Build and run our vulnerability management program - discovery, triage, prioritization based on real exploitability in our environment, and driving remediation to completion with the owning teams - Integrate security into the SDLC in ways engineers actually adopt: code scanning, dependency policy, pre-merge checks, secrets detection, and paved-road libraries and templates - Write the automation, tooling, and services that scale our security work - internal utilities, developer-facing tools, and the plumbing that makes findings actionable. This is an engineering role, not a governance role - Help protect highly sensitive IP and export-controlled technical data, working with our People, IT, and Legal teams on the controls that support it WHO YOU ARE - 8+ years in security engineering, with real depth in at least two of the following and working competence across the rest: application and product security, offensive security, cloud infrastructure security, supply chain and build security, detection and response - Strong application security fundamentals: threat modeling, manual secure code review, common vulnerability classes and their mitigations, and experience running SAST, DAST, and SCA tooli