Hardware System Test Engineer

About Fractile Fractile was founded in 2022 on the bet that, eventually, the world’s most capable AI systems would be limited in their impact by the time taken to produce useful outputs. We bet everything on the logical conclusion: that the only way to truly unlock this latent value, to make speed viable at scale, was to radically re-invent the hardware that we run our frontier AI models on. Ever since, we have been building chips and systems that tackle this problem: how to efficiently generate output at thousands of tokens per second, while handling the complexity and capacity challenges of operating large models at very long contexts. The workloads that push to the limits of the current frontier are already transformational; it is the technical and economic limits on inference speed that are constraining progress. The defining work of the 21st century will be marked by the engine of inference delivering immense and diffuse chains of intellectual inquiry, in drug discovery, in software engineering, in materials discovery, in any field where progress is driven by deep reasoning and intelligence to resolve complex problems. Key Responsibilities • Develop and maintain system-level hardware defect detection tests for individual servers and rack-based systems. • Implement tests to detect assembly defects, marginal components, damaged hardware, cabling or interconnect issues, cooling faults, etc. • Develop service and field diagnostic tests used for RMA triage, repair validation, and preventative maintenance. • Implement deterministic, fast-running tests with clear pass/fail criteria and actionable failure output suitable for manufacturing and service technicians. • Develop PCIe defect detection tests to identify lane faults, link degradation, polarity issues, retimer problems, and intermittent connectivity failures. • Implement stress and soak tests designed to expose latent or marginal hardware issues. • Debug test failures and hardware issues, performing root-cause analysis and escalating design or process issues as appropriate. • Analyze factory and field failure data to identify coverage gaps and propose test improvements. • Support deployment, versioning, and maintenance of test software across factory and service environments. • Collaborate with software development teams to integrate tests into production system software. • Collaborate with hardware, manufacturing, service, and reliability teams to ensure tests align with known defect modes and operational needs. Required Qualifications • 3–7 years of experience in system, server, or hardware test engineering, preferably in manufacturing or service environments. • Solid understanding of server hardware architectures, PCIe fabrics, power delivery, cooling systems, and common failure modes. • Hands-on experience developing or executing hardware defect detection or diagnostic tests. • Experience working in Linux-based test environments. • Familiarity with BMC-based systems and basic use of OpenBMC or Redfish interfaces. • Strong debug skills and the ability to distinguish test issues from real hardware faults. • Ability to write clear test code, logs, and documentation for operational use. Preferred Qualifications • Experience with AI accelerator, GPU, or high-performance compute servers. • Exposure to PCIe Gen4/5/6 systems or other high-speed serial interconnects. • Experience diagnosing intermittent, marginal, or temperature-dependent hardware failures. • Experience working with liquid-cooled or thermally complex server platforms. How we work • Ownership and execution: you will have full agency to drive your work forward • Rapid iteration: we all work directly with top leadership to move from idea to hardware on ambitious timelines • Full-stack engagement: hardware, software, silicon, and modelling teams all work closely together to create a product with generational impact • Optimistic and pragmatic: we possess the will to win, and to do the hard work to get us there • Team player mentality: the mission is bigger than any of us, and we have the curiosity and technical focus to see the best idea shipped, no matter who’s it is What We Offer • Competitive salary: A competitive salary reflective of your experience and the specialist nature of the role. • Equity & Ownership: meaningful equity so everyone shares in the value creation • Benefits: Private Medical, Dental and Vision, Contributory Pension, 25 Days holiday plus bank holidays and Life/Critical Illness Insurance. • Diverse & fun office: we believe the hardest problems get solved by the broadest range of minds. We are committed to Equal Employment Opportunity through attracting and retaining a diverse team and building an inclusive environment. Fractile is seeking to increase the clock speed of global progress, one chip at a time. We’ve recently raised $220M from investors including Founders Fund and Accel and our most important work lies ahead. Join us! Export controls Our work involves technologies subject to UK, US and other international export control regulations. Certain roles may require additional eligibility checks to ensure compliance with applicable law. We'll be transparent about this throughout the hiring process.