The role

We’re searching for Senior Compiler Engineers to join the team building the ML backend (compiler, run-time, and debugger) for our next-generation OPTUs that connect PyTorch, Tensorflow, JAX, and MXNet down to our low-level kernel drivers.Your mission will be to create seamless support for a broad ecosystem of large AI models, and ensure we are pushing the limits of their performance envelope by closely partnering with hardware and modelling teams to understand device trade-offs.

Responsibilities

• Project Ownership: Own and deliver projects on your team's roadmap that unlock key high-impact technical and business milestones that drive the success of Flux.

• Architect & Build: Design and implement our compiler, runtime, and debugger for PyTorch, TensorFlow, JAX, and MXNet on custom hardware.

• Optimise Performance: Apply advanced techniques (layout, fusion, scheduling, tiling) to eliminate bottlenecks and maximise throughput.

• Mentor & Encourage Standards: Lead code reviews, coach peers, and uphold best practices in ML backend and performance engineering for your team.

• Guide Team Direction: Stay ahead of GPU, AI accelerator, and optical computing trends; propose and prototype innovations.

Skills & Experience

• 5+ years of experience in software engineering with a focus on C/C++ programming.

• Deep expertise in ML framework internals, compilers, low-level programming, and optimisation techniques.

• Deep expertise in optimising Tensorflow, PyTorch or JAX deep learning models.

• Deep expertise with multiple toolchains like LLVM, OpenXLA/XLA, MLIR, TVM.

• Practical experience applying machine learning in high-performance computing contexts.

• Strong problem-solving skills and the ability to think critically and creatively.

• Experience in high-pace, dynamic work environments.

• Excellent teamwork and communication skills, with the ability to collaborate effectively with cross-functional teams.

• Bachelor's degree in computer science, electrical engineering, telecoms engineering, mathematics, or a related field.

• Personal projects are a key differentiating factor and hold more weight than other requirements.

Compensation & Benefits

• Starting salary: £174,000+ depending on experience, skills, and location.

• Competitive stock options, you’re not just part of the journey, you will own a piece of it.

• Work from our HQ in King’s Cross, right in the middle of London’s buzzing AI scene.

• Live within 45 minutes of the office? Perfect. Live within 20 minutes? We’ll add an extra location bonus to your salary.

• We offer visa sponsorship and full relocation support (UK and abroad), through a dedicated third-party provider who are on hand to make your move to London as seamless as possible.

• Full BUPA healthcare and dental cover, medical history disregarded.

• High-spec tech for everyone - M4 Macs as standard, M4 Pros for Engineers.

• Sony noise-cancelling headphones and ergonomic setups to keep you comfortable and focused.

• Personal company card to spend on tools that help you do your job - like ChatGPT Pro or anything else that boosts your workflow.

• Healthy, chef-cooked dinners in the office every night, with something for every diet and tastebud.

• Monthly off-site team socials.

• 25 days of paid holiday, plus all the UK bank holidays.

• Access to our in-house 3D printer for personal or work projects.

• Cycle2work scheme.

• Need a caffeine fix? We’ve got you covered with a tab at our favourite local coffee shop.

• We offer a pension plan and salary sacrifice options.

Due to U.S. export control regulations, candidates’ eligibility to work at Flux depends on their most recent citizenship or permanent residency status. We are generally unable to consider applicants whose most recent citizenship or permanent residence is in certain restricted countries (currently including Iran, North Korea, Syria, Cuba, Russia, Belarus, China, Hong Kong, Macau, and Venezuela). Applicants who have subsequently obtained citizenship or permanent residency in another country not subject to these restrictions may still be eligible.

We do not accept unsolicited CVs from recruitment agencies, will not be liable for any fees, and prohibit unauthorised use of our company name in recruitment activities.

Compensation Range: £174K - £234K