About Majestic Labs We're a fast-moving, US-Israeli AI startup building next-generation infrastructure for the world's most demanding AI workloads. Our mission is to accelerate the future of intelligence and make it ubiquitously accessible by delivering full stack custom AI servers optimized for large-scale inference and training. Backed by top-tier investors and led by industry veterans, we're scaling rapidly. We seek forward-thinking engineers and operators who thrive in a collaborative environment and excel at solving complex challenges from first principles. If you want to build infrastructure that fundamentally changes what the world can accomplish with AI, come join us! About The Position We are seeking a Senior Thermal Engineer with 10+ years of experience to own the full thermal design lifecycle of advanced cooling systems for high-performance computing hardware. This is an on-site, individual contributor role for a candidate with deep hands-on expertise in liquid cooling architecture from silicon-level cold plate design through rack-scale fluid infrastructure, CFD simulation, and AI/GPU-based system design. Responsibilities Own end-to-end thermal design from concept through production, spanning SoC-level cold plate development through rack-scale liquid cooling infrastructure, including hybrid air and liquid cooling systems. Design and optimize high-power silicon cold plates, including internal micro-channel geometry, thermal interface integration, and fluid inlet/outlet configuration directly at the SoC package level. Architect and validate rack-level liquid cooling infrastructure including manifold layout, blind-mate quick disconnect integration, and full loop pressure and flow management. Drive CFD simulation efforts to validate cooling strategies for high-density nodes, optimizing fluid flow, pressure drop, and heat transfer from chip to rack. Partner closely with internal hardware teams and external partners to deliver integrated thermal solutions for AI/GPU-based platforms.

Requirements:

10+ years of thermal engineering experience with deep expertise in liquid cooling systems spanning SoC-level and rack-level implementations in high-performance or data center environments. B.S. or M.S. in Mechanical Engineering or a related field. Proven track record of owning at least one full product lifecycle — from concept through high-volume manufacturing (HVM).

Liquid Cooling Expertise:

Expert-level experience in cold plate design for high-power silicon devices and rack-level liquid-cooled manifold systems, including micro-channel optimization, blind-mate quick disconnect integration, and full loop architecture from node to rack scale.

Fluid Systems & Simulation:

Deep understanding of water pressure dynamics, flow balancing, and leak-mitigation best practices, with proficiency in CFD tools (e.g., Ansys Fluent, Icepak, or equivalent) to simulate and validate complex thermal and fluid systems from component to system level. Familiarity with airflow principles and air cooling requirements for high-density server and rack architectures. Direct experience with AI/GPU-based compute architectures and ultra-high-density power delivery systems. Preferred Qualifications Direct experience with thermal interface materials (TIMs), including selection, characterization, and application in high-power assemblies. Deep familiarity with Open Compute Project (OCP) or ORV3 standards. Experience with blind-mate liquid and power interfaces. At Majestic Labs, we are shaping the next paradigm and making AI ubiquitous by building radically better infrastructure across the entire stack-from systems engineering and VLSI to compilers and AI applications. This epic mission requires a relentless culture of innovation, grit, and dedication. Our employees are our most important asset. Have you read the job description and feel you could be a great fit? We seek smart, curious, self-driven individuals who enjoy creative problem-solving and continuous learning. Even if you don't meet all requirements, we'd love to hear from you if you have the mindset to tackle complex challenges. Majestic Labs is an equal opportunity employer deeply committed to diversity of background and thought. If you are ready to dare greatly, learn from mistakes, engage in vigorous debates, and help create a step-function shift in human technical capability-we want to meet you!