Bristol or London

Hybrid: Three days on-site

Fractile is building silicon, systems and software which will redefine the frontier of AI: running the world's most advanced models at radically higher speed and lower cost. We have an exceptional team across hardware and software capable of bringing about this change, and we are growing fast to meet demand and deliver our product at scale.

We're looking for an engineer who wants to own Bazel at scale and build the tooling that powers every part of Fractile, from ML models to kernel drivers to hardware simulation.This is a greenfield Bazel role in a fast-growing deep-tech company building a new class of ML hardware and software from first principles.

What you will work on

• Designing and owning Bazel rules and extensions
• Scaling our monorepo as we grow across Python, C++, Rust, SystemVerilog and ML workloads
• Creating reproducible, multi-language build pipelines
• Optimising CI performance across large compute clusters
• Defining the developer experience for every engineer at Fractile
• Contributing upstream to Bazel rules we depend on

Why this role is unique?

No legacy — you're building the Bazel ecosystem from scratch
Extreme variety — ML, compilers, kernel drivers, simulators, hardware verification
High impact — your work becomes the backbone of the entire engineering organisation
Deep collaboration with Simulation, Runtime, and Hardware teams
Real ownership — you shape how Fractile builds software

What we are looking for

• 5+ years in software or infrastructure engineering
• 3+ years with build systems
• Strong experience with Bazel
• Python scripting and automation
• Experience with CI/CD for large-scale products

Bonus: ML pipelines, GitHub Actions, multi-language build systems, containers

About us

• Founded in 2022, team of 100+ which is expanding rapidly
• Modern, open offices in London and Bristol
• Collaborative, problem-solving culture built on deep curiosity, entrepreneurial initiative and technical fluency

Export control and security clearance

Certain roles may involve working on technologies subject to export restrictions. Applicants may be required to undergo additional eligibility checks to ensure compliance with applicable law.