Networking & Interconnect Systems - 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. As workloads become increasingly disaggregated, the performance of the system is determined not only by where computation happens, but by how efficiently state and data can move between the hardware best suited to each part of the workload. Communication latency sets the boundary on how far that disaggregation can go.

This role owns that boundary. You will develop the communication systems that allow heterogeneous accelerators to operate as parts of one system, working across protocols, memory movement, networking hardware, and the software layers above them. That means understanding where overhead actually comes from, removing assumptions inherited from more general-purpose workloads, and finding new ways to move data directly and efficiently across vendor boundaries. The remit is intentionally broad: from RDMA paths and programmable NICs to cache transfer formats and emerging interconnect technologies, you will own the technical strategy for making communication less of a constraint on the systems we can build.

What You'll Build

• Characterise and simplify communication paths between accelerators, tracing latency and unnecessary overhead across networking, runtime, memory, and device layers

• Develop faster data movement across heterogeneous hardware, exploring RDMA, programmable NICs, DPUs, switches, and software approaches to cross-device memory management

• Build flexible mechanisms for transferring model state across accelerator types and execution strategies, including KV cache connectors across different forms of parallelism

• Evaluate existing and emerging scale-up and scale-out fabrics, informing cluster architecture, infrastructure integration, and how heterogeneous accelerator communication should evolve

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.