Accelerator Systems Software - Member of Technical Staff

About Us Artificial intelligence scaled on a bet - that bigger models, more identical chips, and more data would keep delivering. As problems grow more complex and the requirements of intelligence more diverse, that bet is breaking down. The next era belongs to heterogeneous intelligence: diverse models on diverse chips, each with distinct strengths, co-evolving into systems of capability unreachable by any single model or accelerator. Callosum is the Intelligent Systems company. We built the infrastructure to make that possible. Our co-evolution engine optimises simultaneously across workflows, agents, and silicon. We launched in early 2026 showing orders of magnitude improvements in performance and a shift in the cost-performance frontier that no single chip or model provider can provide. We believe intelligence comes from the system, not the model. We are scientists and engineers solving what others consider impossible. If you thrive on hard problems, and are passionate and energised by the scale of the challenge, we'd love to hear from you. About the Role Callosum believes that orders of magnitude improvements in AI systems will come through application-aware orchestration across heterogeneous hardware. We are building that vision: infrastructure that treats the full landscape of compute as a unified, co-evolving system. Callosum is purposefully placed to be the first place to access and deploy new chips, expanding beyond GPUs to enable a system that works in harmony, greater than the sum of its parts. This role sits at the foundation of Callosum’s stack, enabling the company to run AI workloads beyond the constraints of any single hardware vendor. You will build the low-level systems software - kernels, drivers, runtime tools - that make diverse and novel accelerators viable for real-world inference, surfacing the full strength of new silicon. This infrastructure is what enables us to turn a fragmented accelerator landscape into our platform; you will own the design decisions that directly influence performance and reliability. What You'll Build Build and maintain kernels, device drivers, and firmware for heterogeneous accelerators Design and implement accelerator scheduling at the execution level — kernel launches, dataflow optimisation, and resource management across diverse hardware Optimise execution paths for latency, throughput, and resource utilisation across accelerator types Work closely with internal teams and hardware vendors to onboard new accelerator platforms Contribute to low-level runtime software that bridges our inference stack and the underlying hardware What You Bring Demonstrable interest in a variety of accelerator microarchitectures Deep experience in kernel development, device driver authoring, or firmware engineering Familiarity with accelerator programming models (CUDA, ROCm, or vendor-specific SDKs) Experience with compiler infrastructure such as MLIR or LLVM Strong debugging skills in environments with limited tooling and incomplete documentation What We Offer Competitive Salary, determined by skills and experience Equity & Ownership Private healthcare We offer Visa sponsorship and relocation benefits to hire the best in the world We work in person at our London office. You'll have the tools, space and setup to do your best work, and if you have specific needs, just tell us We're committed to building an inclusive workplace where everyone feels welcome, and believe in equal opportunities for all.