Senior Modelling Engineer

Bristol or London — Hybrid Fractile is building a new class of AI accelerator — designed to run the world’s largest language models dramatically faster than existing systems. To do this, we build high‑fidelity pre‑silicon models that shape architecture, performance, and product design long before hardware exists. This is where you come in. We’re expanding a high‑calibre simulation and modelling team that already includes engineers with deep expertise in C++, verification, and architectural modelling. You won’t be joining a small “support function”, you’ll be joining the group that defines how Fractile’s hardware behaves. What you’ll work on: 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 Early software development on virtual platforms You’ll work closely with hardware, software, and ML teams in a true hardware–software co‑design loop — not a siloed modelling function. Fractile’s Simulation team is growing and includes: C++ and SystemC specialists Verification and validation engineers System architects Embedded Engineers You’ll be joining a team with r eal depth , not a lone modelling role. What we’re looking for: You may be a fit if you have 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 We’re especially interested in engineers who can operate across architecture, performance, and functional correctness. Nice to have: Experience with ML workloads or ML accelerator architectures Prior startup or small‑team experience Why this role matters: 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 Reduce risk across the entire product lifecycle This is high‑leverage engineering — the kind that changes the trajectory of the hardware. About Fractile Founded in 2022 and scaling fast. Modern offices in London and Bristol. Hybrid working: 3 days onsite, 2 days remote. A collaborative, curiosity‑driven engineering culture