About the OrganisationOur client is a next‐generation defence technology organisation developing advanced, software‐defined systems that support allied military and national security capabilities. Operating at the intersection of autonomy, AI, distributed systems, and secure infrastructure, the organisation builds platforms where speed, reliability, and security are mission‐critical.The Australian team is delivering highly innovative unmanned and autonomous systems, working across multiple security domains and classification levels. This is a rare opportunity to join a technically ambitious organisation shaping the future of defence‐grade software and systems engineering.About the RoleWe are seeking an experienced Senior Site Reliability Engineer (SRE) to design, build, and operate next‐generation software delivery and sustainment platforms.This role is central to enabling the rapid, secure, and resilient delivery of complex software systems across cloud, on‐premise, and hybrid environments. You will work across the full stack—from infrastructure and operating systems through to orchestration and application platforms—while acting as a technical leader and mentor within multidisciplinary engineering teams.The role suits someone who enjoys deep technical ownership, complex systems, and operating in environments where reliability directly supports national capability.Key ResponsibilitiesPlatform & Toolchain EngineeringLead the design, implementation, and support of modern software delivery toolchains enabling continuous, secure delivery across multiple security domainsArchitect and operate cloud and hybrid infrastructure, including platforms such as AWS, Azure, and VMwareContribute to and evolve build, deployment, and release systems, including Nix‐managed environmentsInfrastructure & Systems OperationsManage systems across multiple layers:Infrastructure: Cloud platforms and virtualised environmentsOperating Systems: Linux (e.g. Ubuntu, Red Hat, NixOS) and WindowsOrchestration: Kubernetes, OpenShift, Docker, TerraformApplications: CI/CD platforms, source control, and internal toolingSupport limited management of physical ICT hardware where requiredReliability, Security & AutomationAdvocate for and implement best‐practice security controls throughout the software delivery lifecycleImprove system reliability, scalability, and observabilityTroubleshoot and analyse remotely deployed systems in complex operational environmentsLeadership & CollaborationAct as the technical owner for services, including roadmap planning, stakeholder engagement, and lifecycle managementMentor and support engineers from diverse technical backgroundsCollaborate closely with software, systems, and operations engineers to deliver secure, reliable platformsThe Successful CandidateYou will be a senior‐level engineer with strong experience operating complex software systems at scale.Required experience and skills include:Bachelor's degree in Computer Science, Software Engineering, or equivalent practical experienceProven experience in a senior SRE, platform, or infrastructure engineering roleStrong background designing and operating horizontally scaled cloud systemsExperience working across the full software lifecycle: design, implementation, operation, and sustainmentAbility to take end‐to‐end ownership of services, including technical leadership and coordinationStrong problem‐solving skills and ability to operate in high‐stakes environmentsEligibility to obtain and maintain an Australian Government Security ClearanceDesirable ExperienceExperience developing cloud‐native services in C++, Rust, Python, or GoExperience with NixOS and the Nix programming languageStrong understanding of systems programming concepts (concurrency, optimisation, performance)Infrastructure‐as‐code experience using TerraformStrong networking fundamentals in cloud and hybrid environmentsDeep experience deploying and operating Kubernetes clustersInterest in progressing into technical leadership or engineering management rolesWhat's on offer?Long term role working on cutting‐edge, defence‐grade technologyACT ‐based position within a highly skilled, mission‐focused engineering teamCompetitive salary package (aligned to senior‐level market rates)Long‐term career growth across principal engineering or leadership pathwaysOpportunity to work on systems of national and strategic importance