Accelerator Systems Software Engineer – Member of Technical Staff

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. 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.

Key responsibilities

• 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.

Required profile

• Demonstrable interest in a variety of accelerator microarchitectures.
• Deep experience in kernel development, device driver authoring, or firmware engineering.
• Familiarity with accelerator programming models such as 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.

Required skills

• Kernel development
• Device driver authoring
• Firmware engineering
• CUDA
• ROCm
• Vendor‑specific SDKs
• MLIR
• LLVM
• Advanced debugging

What we offer

• Competitive salary determined by skills and experience.
• Equity & ownership.
• Private healthcare.
• Visa sponsorship and relocation benefits.
• On‑site work in our London office with full tools and setup.
• Inclusive workplace with equal opportunity for all.