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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. We're growing fast, and we don't post everything. Over the next year we're hiring across silicon, hardware test, manufacturing operations, device software, compilers, performance simulation and the teams that keep all of it running. Some of those roles are live on this page. Plenty aren't yet. If you've read what we're building and want to work on it, send us your details. Tell us which area interests you and what you've worked on that's relevant. We'll come back to you when something fits. This isn't a formality. We read these, and several of our team joined this way. 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. Find Jobs in United Kingdom on Arbeitnow

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. The Role We are seeking a senior Semiconductor Test Engineering leader to drive manufacturing test strategy and silicon production readiness for next-generation AI accelerator devices. This role combines deep technical expertise in high-performance compute silicon with leadership responsibility for internal product engineering teams and external development partners. The successful candidate will oversee all aspects of production test development — from DFT strategy and ATE bring-up through silicon characterisation, yield optimisation, advanced packaging test, and high-volume manufacturing ramp — ensuring robust, scalable, and cost-effective test solutions for advanced AI accelerator platforms. Key Responsibilities Drive the manufacturing test strategy for an AI accelerator chip featuring PCIe Gen6, LPDDR, advanced CMOS nodes, and advanced packaging (e.g., 2.5D/3D, chiplet). Lead and manage a team of chip test engineers responsible for test planning, test program development, pattern bring-up, silicon characterization, debug, and optimization. Manage subcontracted test development partners (OSATs, ATE vendors, external engineering services). Includes scoping, technical oversight, schedule tracking, and quality control of deliverables. Define and drive test software architecture, DFT usage, and test pattern development strategies for high-speed logic, SRAM, DRAM, and High Speed IO blocks. Work closely with design, DFT, product engineering, packaging, and validation teams to ensure robust test coverage, manufacturability, and yield ramp success. Oversee test development for high speed interfaces such as PCIe Gen6 and multi-GHz LPDDR. Guide development of structural and functional test content (scan, MBIST, JTAG, HSIO tests, system-level tests). Lead silicon bring-up and development on ATE: correlation, failure analysis, shmooing, corner testing, stress testing, and yield improvement activities. Define KPIs and metrics for subcontractor performance, test coverage, yield, time-to-test, and cost optimization. Drive continuous improvement in test methodologies, automation, data analytics, and debug infrastructure. Ensure robust test flows for advanced packaging (thermals, interposer/bridge connections, TSV integrity, die-to-die IO testing). Support qualification, reliability testing, and high-volume manufacturing transfer. Required Qualifications 8+ years in semiconductor test engineering, including leadership or technical lead roles. Deep experience with ATE test development (e.g., Advantest 93K, Teradyne). Strong understanding of DFT (scan, ATPG, LBIST, MBIST), memory testing, and high-speed interface testing. Experience managing external test development partners or OSATs. Proven ability to lead and mentor test engineering teams. Solid background in advanced CMOS nodes and familiarity with advanced packaging test challenges. Expertise in silicon debug, characterization, and correlation across ATE and system-level environments. Ability to collaborate across design, architecture, product engineering, packaging, and operations.. Preferred Qualifications Experience with AI/ML accelerator chips or other high-performance compute ICs. Prior involvement with PCIe Gen5/Gen6 or LPDDR4/5/6 test methodologies. Familiarity with signal-integrity-aware test development and high-speed IO margining. Experience with chiplets, 2.5D/3D IC test flows, or heterogeneous integration. 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. Find more English Speaking Jobs in United Kingdom on Arbeitnow

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. The Role We are looking for Senior ML Compiler Engineers with experience in machine learning compilation to work on the compiler stack for our ground-breaking AI accelerators. You can be based in our Bristol office or London. Fractile isn't another AI startup gluing together frameworks. We are designing a full-stack execution engine: hardware, compiler, runtime, to build the world's largest language models 100 x faster than today's systems. That ambition forces us to rethink everything from first principles. For compiler engineers, this is a rare moment: the architecture is still being shaped. The IR, the lowering strategy, the optimisation passes, the execution model - you get to define its future. In this role, you will: Develop the machine learning compiler stack for Fractile's innovative AI acceleration hardware Enable industry-leading performance of the latest LLMs on Fractile's accelerators Work with hardware, driver runtime, and ML engineers in a highly collaborative hardware-software co-design methodology It would be great if you have: Proven experience of the development of machine learning compilers using industry standard technologies such as MLIR or TVM Up-to-date knowledge of machine learning techniques and technologies A good understanding of computer architecture and performance optimisation techniques Excellent C/C++ skills and solid experience of industry standard development tools and technologies An creative and innovative mindset, and a willingness to take ownership and drive results in a fast-paced environment Computer Science, Electronic Engineering, Maths, Physics, or related degree and 4+ years of industry experience You may also have: Previous experience in a startup or small team environment 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. Find Jobs in United Kingdom on Arbeitnow

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. The role We build the control chain that powers on, monitors, updates, and protects devices and racks across bare metal, RTOS, and embedded Linux. We also build the communication mechanisms that connect devices to each other and to the host. Security runs through all of it. A chain of trust from the hardware up to the rack management plane: the root of trust each controller boots from, the signed updates that reach the fleet safely, the identity that lets a device prove what it is, the authenticated channels the controllers and devices talk over, and the runtime protections that keep the host Linux kernel and the on-die firmware trustworthy long after boot. These are the layers that let operators rely on the hardware. You'd be deeply involved in that security across the chain, making it real in software. You'll work hand in hand with our architecture and hardware teams, bringing the software and system-level view: turning threat models into concrete mechanisms in bare metal, RTOS, and Linux, then designing, prototyping, and validating them. Some of the calls in this model are still open, and you'll help shape them. We want engineers who understand security from the inside out. You know how the root of trust, boot chain, key hierarchy, and secure interconnects actually work under the hood, not just how to switch them on. In this role, the security of your software solutions depends entirely on how well you understand the hardware beneath it. Some of the protections we rely on live in silicon, some in software, and part of the skill is knowing which belongs where. We're looking for people who know both sides well enough to build the mechanisms that close whole classes of bugs by design. We're not heavy on levels here! Whether you'd call yourself senior, staff, principal, or lead, what matters is depth of security judgement, system-level experience, and working well with the engineers around you. If you've worked deep in the security of real systems and like to get your hands on the code and the systems around it, we'd like to hear from you. What you'll do: Shape the security of the control chain (device, board, chassis, and rack controllers): threat models, trust boundaries, and a coherent secure-by-design approach across all platforms Design and help build secure boot and the root of trust on each controller: verified/measured boot, signing and verification, anti-rollback, and locking down debug and privileged access in production Secure the interconnects, between controllers and between devices and the host, with authentication, integrity, and additional protections where needed Design and build the cryptographic mechanisms: key hierarchies, provisioning and storage, device identity, and remote attestation so the fleet can prove what it's running Make firmware updates safe end to end: signed images, rollback protection, staged rollout, and clean recovery, across every hop of the chain Protect the running system, not just boot: harden the host Linux kernel and the on-die firmware Work closely with hardware and the rest of the software team to build security into the product, running threat-model reviews, triaging vulnerabilities, and driving fixes to closure What we're looking for: We expect you to know the fundamentals, and to have real, practical experience across several of these: An adversarial mindset and sharp threat-modeling instincts: trust boundaries, assets, attacks, and honesty about residual risk Hands-on experience with the core security primitives in software and in silicon: secure boot, root of trust, cryptography, and key management, including how they're implemented and where they can fail Secure protocol and channel design between components Strong C and Rust, and the instinct for memory safety and defensive coding that low-level security work needs Experience building, not just using, security mechanisms: a secure-boot chain, key hierarchy, or attestation flow you shaped That's the core. We get especially curious about your application when you also bring some of the following. Very few candidates tick every box here, and we don't expect you to: Attestation at boot and at runtime, and management-plane protocols (DICE, IETF RATS, SPDM, MCTP, PLDM; confidential-computing directions like TDISP) Hardware building blocks and firmware/Linux hardening (HSM, TPM, secure element, Caliptra, secure debug; open firmware/boot projects, image minimisation) Assurance and resistance (supply-chain security with SBOM and SLSA, fuzzing and testing, standards like NIST 800-series, Common Criteria, OCP incl. S.A.F.E., TCG/DMTF; physical and side-channel awareness) AI/LLM-assisted security tooling, and RISC-V / GPU / ML-accelerator experience What you're signing up for: This is a young company doing hard things, balanced across hardware and software. We're building the software layer for a whole inference system as it takes shape, so you'll often be securing systems ahead of the hardware: reasoning about a threat model against a specification first, then a simulator, then early boards. You'll work with incomplete information and watch it get sharper with every iteration. That takes comfort with ambiguity and a bias for action. If that sounds daunting, this may not be the role. If it sounds like the fun part, we should talk. Boundaries between areas are soft here. Security touches every layer, so you'll work across bare metal, RTOS, and Linux, and alongside the architecture and hardware teams as much as the rest of the software team. That breadth is a good part of the job. You'll be there for first bring-up, the first secure boot that verifies, the first device that attests itself, the first clean end-to-end run. A piece of what you built will live in silicon and in every rack we ship. We want a team that reflects the world it's built for, and we welcome applicants from every background, including those whose path here hasn't been a straight line. We care that you're excited by this kind of work, that you bring security rigour, and that you make a team better. 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. Find Jobs in United Kingdom on Arbeitnow

About Nebius: Nebius is leading a new era in cloud infrastructure for the global AI economy. We are building a full-stack AI cloud platform that supports developers and enterprises from data and model training through to production deployment, without the cost and complexity of building large in-house AI/ML infrastructure. Built by engineers, for engineers. From large-scale GPU orchestration to inference optimization, we own the hard problems across compute, storage, networking and applied AI. Listed on Nasdaq (NBIS) and headquartered in Amsterdam, we have a global footprint with R&D hubs across Europe, the UK, North America and Israel. Our team of 1,500+ includes hundreds of engineers with deep expertise across hardware, software and AI R&D. The role We're looking for a Senior Software Systems Engineer to join our team and play a key role in the development of our cutting-edge hyperscaler platform. The GPU & InfiniBand team is responsible for enhancing and optimizing the core components of our Cloud platform, with a specific focus on GPU computing, InfiniBand networks, and the KVM/QEMU stack. You'll work closely with hardware virtualization and device emulation technologies, ensuring high performance and security in multi-GPU, HPC environments. The role involves analyzing, troubleshooting, and improving infrastructure to support new hardware, fine-tuning system performance, and automating fault detection and resolution in a complex system. In this position, you will be responsible for: Tuning the performance of GPU clusters and InfiniBand networks to ensure optimal operation in HPC and GPU-based environments. Analyzing and troubleshooting the root cause of issues related to GPUs and InfiniBand networks, and proposing corrective actions. Integrating new hardware into the existing infrastructure, including support for new GPU hardware through software stacks like Kubernetes, QEMU, and KVM. Enhancing automation systems for proactive monitoring, detecting, and resolving issues in GPU and InfiniBand environments. Configuring and managing GPU devices and InfiniBand fabrics, ensuring efficient and reliable operation. We expect you to have: 5+ years of professional experience in system-level software development (focused on performance optimization, low-level programming). 3+ years of hands-on experience with Linux systems (administration, troubleshooting, and performance tuning). In-depth understanding of server architecture, including PCIe devices, NICs, Linux OS/Kernel, and high-performance computing (HPC) systems. Strong proficiency in one or more performance-oriented programming languages (C/C++, Go, Python). It would be a plus if you have: Experience with GPU end-to-end testing in a cluster environment using InfiniBand networking. Proven track record of analyzing and optimizing the performance of HPC workloads (e.g., simulations, data analysis, AI/ML workloads). Familiarity with RDMA, RoCE, and InfiniBand protocols for high-performance communication. Background in Software-Defined Networking (SDN) and experience with HPC cluster networking . Understanding of QEMU/KVM virtualization and managing virtualized environments. Experience with deep learning frameworks such as PyTorch and TensorFlow , and their integration with HPC systems. Familiarity with collective communication libraries like MPI and NCCL for distributed computing. We offer competitive salaries ranging from $170k-$300k + equity based on your experience. We conduct coding interviews as part of the process. #LI-LH2 Benefits & Perks: Competitive compensation Career growth and learning opportunities Flexibility and ownership Collaborative and innovative culture Opportunity to work on impactful AI projects International environment and talented teams What's it like to work at Nebius: Fast moving - Bold thinking - Constant growth - Meaningful impact - Trust and real ownership - Opportunity to shape the future of AI Equal Opportunity Statement: Nebius is an equal opportunity employer. We are committed to fostering an inclusive and diverse workplace and to providing equal employment opportunities in all aspects of employment. We do not discriminate on the basis of race, color, religion, sex (including pregnancy), national origin, ancestry, age, disability, genetic information, marital status, veteran status, sexual orientation, gender identity or expression, or any other characteristic protected by applicable law. Applicants must be authorized to work in the country in which they apply and will be required to provide proof of employment eligibility as a condition of hire. If you need accommodations during the application process, please let us know. Find Jobs in Germany on Arbeitnow

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. The role Fractile is building a full-stack AI accelerator from the ground up, and the compiler team sits at the heart of how we deliver performance. As the Engineering Manager for Compilers, you will build and lead a team of 10+ engineers developing the compiler stack for our novel AI acceleration hardware, with direct responsibility for enabling industry-leading LLM inference performance on Fractile's accelerators. This is a hands-on technical leadership role in a fast-moving, collaborative environment where the compiler team works closely with hardware, driver, runtime and ML engineers across the stack. If you want to shape the architecture of a compiler from first principles, build a world-class team around it, and have your work directly determine the performance of next-generation AI hardware, this is the role. What we're looking for: Proven track record of leadership experience managing a high-performance development team and delivering consistently outstanding outcomes. Proven experience in compiler development, with experience of machine learning compilers and industry standard technologies such as MLIR or TVM being a significant advantage. Up-to-date knowledge of machine learning techniques and technologies A good understanding of computer architecture and performance optimisation techniques. Excellent C/C++ skills and solid experience of industry standard development tools and technologies. A creative and innovative mindset, and a willingness to take ownership and drive results in a fast-paced environment. What you're signing up for: This is a young company doing hard things, at the intersection of novel silicon and the software stack that makes it useful. You'll be building and leading a compiler team as the hardware it targets is still taking shape, which means making architectural decisions against a specification first, then a simulator, then early silicon. The IR design, the lowering strategy, the execution model: you'll help define all of it before you can run it on real hardware. That takes comfort with ambiguity and the ability to make good calls with incomplete information. If that sounds frustrating, this probably isn't the role. If that sounds like the interesting part, we should talk. The boundaries here are soft by design. The compiler team works closely with hardware architects, kernel engineers, runtime teams and ML researchers. You'll need to understand enough of what sits above and below your layer to make good decisions at the boundary, and to build a team that can do the same. That breadth is a feature of the job, not a distraction from it. You'll be there when the first model runs end to end on Fractile silicon. When the lowering strategy you helped design produces a result the hardware team didn't think was possible yet. When the team you hired and grew ships something that goes into every rack we sell. We want a team that reflects the world it's building for, and we welcome applicants from every background, including those whose path here hasn't been straight. We care that you're energised by this kind of work, that you build and develop great engineers, and that you make the people around you better. Come build it with us. 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. Find more English Speaking Jobs in United Kingdom on Arbeitnow

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. The Role This role sits at the boundary between host and silicon. The kernel driver is key to keeping pace with our ultra-fast devices on cutting-edge server platforms. It's a high-leverage layer where each win shows up as real throughput and latency gains. You'll be there for the pre-silicon simulations, first bring-up, first end-to-end runs, and the moments where performance jumps because of something you shipped. What you'll do Design, develop, and maintain the Linux kernel driver for Fractile's AI accelerator Build the performance-critical kernel-space paths that keep the host stack moving: PCIe device management, DMA, memory handling, interrupt handling, and robust recovery paths Define and evolve the userspace interface the runtime depends on, with a focus on stability, debuggability, and performance Work in a tight co-design loop with hardware, firmware, runtime and ML engineers: validate assumptions, iterate on behaviour, and close gaps early Improve tooling/workflows so we move fast without breaking things What we're looking for You've shipped and maintained Linux kernel device drivers in production. Experience with PCIe-attached devices and custom hardware interfaces is ideal. Strong systems and performance instincts. You can reason about computer architecture, concurrency, and where the time goes Excellent C and/or Rust, and a pragmatic approach to building high-quality, maintainable & secure kernel code You enjoy hard kernel and system-level problems, and you take them end-to-end until the measurements move Computer Science, Electronic Engineering, Maths, Physics, or related degree and 3+ years of industry experience Nice to have GPUs / ML accelerators / high‑throughput I/O (NICs, RDMA, storage) Hardware bring‑up or pre‑silicon simulation experience Performance work: profiling, tracing, benchmarking, regression tracking If you want to build the software where every driver win unlocks huge system performance, come build it together. 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. Find Jobs in United Kingdom on Arbeitnow

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. The Role We build the control chain that powers on, monitors, updates, and protects devices and racks across bare metal, RTOS, and embedded Linux. It's production-critical software that keeps racks stable, updates safe, and hardware secure. It's a critical layer in turning a tokens per second benchmark into a tokens per month system, turning great silicon into reliable output at rack scale. You'll be there for the first racks coming to life and rollout days where update safety matters. Your work makes the difference between a bad failure and a clean recovery path. This is the work that makes the system something operators can trust. What you'll do Develop firmware and services for management controllers at every level: rack management, BMC, and board/device controllers (RTOS and bare metal) Build systems software for board and rack management, from early bring-up through to production deployment Implement the critical flows that keep fleets healthy: power-on and provisioning, monitoring/telemetry, updates, recovery, and security Integrate with the wider host/device stack (drivers and runtime libraries) so the system works end-to-end Work closely with hardware and device software teams to define reliable interfaces, validate behaviour, and debug boundary issues What we're looking for Proven experience shipping production-critical, reliable embedded systems across two or more of: bare metal, RTOS, embedded Linux (or deep expertise in one with clear ability to ramp the others) Strong C and/or Rust, and excellent engineering judgement around safety, testing, debugging, and failure modes A reliability-first mindset: you design for observability, diagnosability, and recovery paths that are predictable and testable Comfortable working close to the hardware/software boundary (bootloaders/BSP/kernel-adjacent work) and collaborating tightly with HW, driver, and runtime teams Collaborative and high-ownership. You communicate clearly, move fast, and enjoy working through hard problems with others Computer Science, Electronic Engineering, Maths, Physics, or related degree and 3+ years of industry experience Nice to have Embedded platform / systems firmware experience (board management, BMC-style stacks, rack controllers) OpenBMC experience and/or embedded Linux image build/customisation experience Zephyr (or similar RTOS) experience Security-minded, with practical instincts around secure boot, signed updates, device identity, and designing systems that fail safe and recover cleanly (direct experience in some areas is a plus) Kernel device work (drivers, device tree, bring-up, perf/trace) Hardware bring-up experience, including lab tools (logic analysers, oscilloscopes, waveform viewers) RISC-V familiarity Experience with GPUs or ML accelerators If you want to build the control software that keeps rack-scale systems stable, safe, and secure for next-gen AI, come build it together. 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. Find Jobs in United Kingdom on Arbeitnow

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. About the Software organisation at Fractile PerfSim sits within the Software organisation at Fractile, which is responsible for developing a full software stack for our groundbreaking AI inference systems. That's everything from ML compilers, device drivers and systems firmware, application level runtime and ecosystem integrations, ML and compute libraries, great developer tooling and a full portfolio of simulators, through to datacenter scale workload deployment solutions. At Fractile, we know that a fantastic software stack is a critical and central part of any AI inference solution and it sits at the heart of everything we're doing. About the team and role To build hardware that doesn't yet exist, you first have to model it — with precision, depth, and an eye for the trade-offs that matter. At Fractile, high-fidelity pre-silicon models shape our architecture, performance, and product design long before hardware exists. The Simulation team includes C++ and SystemC specialists, verification and validation engineers, system architects, and embedded engineers. This is not a support function — it is the group that defines how Fractile's hardware behaves. As a Modelling Engineer you will develop the pre-silicon models of Fractile's AI acceleration hardware, enabling architectural exploration and definition, functional modelling, performance modelling and bottleneck analysis, and early software development on virtual platforms. You will work closely with hardware, software, and ML teams in a true hardware–software co-design loop. About you You have a genuine curiosity for hard problems and the depth to operate across architecture, performance, and functional correctness. You understand that the models you build will shape the architecture of Fractile's accelerator, determine performance trade-offs, enable early runtime and compiler development, unblock software teams months before silicon exists, and reduce risk across the entire product lifecycle. You take that responsibility seriously and bring the rigour it demands. Key Requirements Experience in pre-silicon modelling of complex semiconductor IP SystemC or equivalent modelling frameworks C++ for high-performance simulation Performance modelling and architectural analysis Verification and functional modelling Nice to Have Experience with ML workloads or ML accelerator architectures Prior startup or small-team experience 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. Find more English Speaking Jobs in United Kingdom on Arbeitnow

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 Own and define the DFT architecture for a large AI accelerator SoC (scan, compression, MBIST, LBIST, boundary scan) Set DFT strategy, methodology, flow and signoff criteria Drive integration of DFT tools and flows into the overall EDA environment Define hierarchical DFT approach for multi-core designs and large memory systems Define scan architecture, compression strategy, and ATPG approach Define memory test and repair strategy for large embedded RAM Establish power-aware and at-speed test strategies Work closely with RTL and physical design to ensure clean DFT integration and timing closure Work with test and product engineering teams to bring up and debug ATPG patterns on ATE, supporting production test and yield ramp Mentor and guide DFT engineers Required Experience Strong experience in DFT for complex ASIC/SoC designs (typically 8+ years) Proven ownership of DFT architecture on at least one large tapeout Deep expertise in scan, compression, ATPG, and MBIST Experience with industry tools (Synopsys or Tessent) Strong understanding of clocking, resets, power domains, and physical constraints Experience with silicon bring-up, debug, and yield ramp Profile Comfortable owning ambiguous, high-impact problems Balances architectural thinking with hands-on execution Sets direction while staying close to implementation details 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. Find more English Speaking Jobs in United Kingdom on Arbeitnow

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: Create and support Python tooling and silicon verification and physical design workflows centred around silicon EDA tooling, which will require coding and build-system knowledge to assist with tasks faced by different teams. Bazel build system support for new silicon EDA tools required for throughout the chip lifecycle Create and improve Python developer tools across frontend and backend silicon teams Improve existing workflows to make them cacheable and reproducible Work with the engineering team to build and optimise their workloads It would be great if you have: Experience of silicon EDA tooling Experience working with build systems tooling, such as Bazel. Experience working with workload management tools, such as Slurm. Experience working with container orchestration tools, such as Docker, and Kubernetes. Experience working with infrastructure as code, such as Ansible, or Terraform and maintaining compute infrastructure Experience of setup and monitor observation tooling for resource utilisation, machine failures, and more (e.g. Prometheus/Zabbix) Preferred Qualifications: Proficient in modern software development language(s) especially Python Proficient dealing with modern build systems e.g. Bazel, Pants Past experience with diagnosing and resolving network/storage/CPU/RAM bottlenecks across complex workloads. Experience deploying and managing a grid compute system (Slurm/LSF/SGE). Proficiency with containerisation frameworks (Docker/Singularity) 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. Find more English Speaking Jobs in United Kingdom on Arbeitnow

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. We are looking for a highly motivated and experienced RTL Design Engineer to join our dynamic team. In this role, you will play a key part in the design and implementation of digital systems, contributing to every stage of the project lifecycle. Your work will involve developing and optimising Register Transfer Level (RTL) designs for high-performance and power-efficient systems RTL Development and Implementation: Develop and maintain RTL specifications for digital designs, ensuring clarity and accuracy. Implement complex design modules with a focus on performance, power, and area efficiency. Take ownership of design tasks, including planning, execution, and delivery of work packages. Define design tasks for the project, including partitioning, interface specifications, and module definitions. Collaborate with verification engineers to ensure functional correctness through simulation and formal verification. Cross-Functional Collaboration: Work closely with physical design engineers, and verification teams to ensure seamless integration of the design. Documentation and Standards Compliance: Document RTL design methodologies, module interfaces, and functional requirements. Ensure adherence to coding standards, best practices, and maintainability guidelines. Qualifications and Skills: Education: Bachelor's, Master's, or Ph.D. in Electrical Engineering, Computer Engineering, or a related field. Experience: 6+ years of experience in digital design, RTL development, or related roles. Proven expertise in developing RTL designs for high-performance systems. Familiarity with advanced digital design concepts, such as pipelining, clock-domain crossing, and power gating. Experience with high-speed or low-power design methodologies. Soft Skills: Strong analytical and problem-solving skills. Effective communication and collaboration abilities in cross-functional teams. A detail-oriented approach with a focus on quality and efficiency. 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. Find more English Speaking Jobs in United Kingdom on Arbeitnow