Accelerator Systems Software - Member of Technical Staff
Callosum
IT
London, UK
Location
London
Employment Type
Full time
Location Type
On-site
Department
Intelligent Systems Engineering
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