Modelling Engineer (Mid-Level or Senior)

Modelling Engineer (Mid-Level or Senior) Fractile · London or Bristol · Full-time · Hybrid About Fractile Fractile is building a new class of AI accelerator — designed to run the world's largest language models dramatically faster than existing systems. Founded in 2022 and scaling fast, we work at the intersection of cutting-edge hardware and software, in modern offices in London and Bristol. If you want your work to directly shape the future of AI infrastructure, you'll fit right in. The Role To build hardware that doesn't yet exist, you first have to model it — with precision, depth, and an eye for the trade-offs that matter. At Fractile, high-fidelity pre-silicon models shape our architecture, performance, and product design long before hardware exists. This is where you come in. You'll be joining a high-calibre simulation and modelling team that includes engineers with deep expertise in C++, verification, and architectural modelling. This isn't a support function — it's 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. No silos — just tight collaboration across disciplines. The Team 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 real depth — not a lone modelling role. What We're Looking For We care about depth of knowledge and a genuine curiosity for the problems we're solving. You may be a strong 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. Bonus Points These aren't requirements, but they'd make you stand out: • 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. Why Fractile • Work on genuinely hard problems at the frontier of AI hardware • A collaborative, curiosity-driven engineering culture • Hybrid working: 3 days onsite, 2 days remote • Modern offices in London and Bristol — choose your base • Competitive salary and equity Fractile is committed to building a diverse and inclusive team. We welcome applications from people of all backgrounds and actively encourage candidates from underrepresented groups to apply.