Lumai is redefining how the world computes. We are an ambitious, venture-backed UK startup pioneering a breakthrough AI accelerator for data centers which uses 3D optical compute. Our radical technology uses light to perform computation at orders of magnitude faster speeds and at far greater scales than ever before, all whilst consuming far less energy than traditional approaches.
Lumai is unlocking performance and efficiency gains that could transform the economics of AI and compute infrastructure and reshape how intelligence scales globally.
If you are passionate about bringing groundbreaking technology to market, and want to be part of a team pushing the boundaries of what is physically possible, Lumai is where you can make it happen.
Founded in 2022, Lumai is a University of Oxford spinout using optical processing to accelerate large language models (LLMs) and other transformer-based AI systems. The team combines expertise in optical computing, machine learning, and physics.
Lumai has already secured over $15 million in investment from leading deep-tech investors like Constructor Capital, IP Group, PhotonVentures and government grants, and is scaling rapidly to deploy the fastest optical compute currently available globally.
We are looking for a Head of Software for Lumai's AI Application team, who will set the technical direction for how AI workloads are developed, optimised, and deployed on our accelerator hardware. This is a rare opportunity to shape a team's culture and architecture from day one — you will be both a hands-on engineer and the technical anchor for a distributed team of five (growing to ten within 18 months).
Own the end-to-end technical architecture of the AI application software stack, from SDK surface to inference runtime
Drive engineering decisions around framework integration, model optimisation strategies, and hardware abstraction layers
Conduct design reviews, set coding standards, and mentor engineers across inference, SDK, and tooling workstreams
Act as the primary technical liaison between the remote European team, HQ architects, and the simulation team
Collaborate directly with the System and HW Architects on SW/HW co-design requirements
Lead hiring interviews for the team; contribute to technical roadmap planning with engineering leadership
Maintain hands-on delivery — writing and reviewing production-quality code alongside the team
Must-Have
7+ years of software engineering experience, with at least 2 years in a tech lead or equivalent senior individual contributor role
Deep expertise in AI/ML systems — inference pipelines, ML framework internals, model optimisation, or accelerator programming
Strong Python and C/C++ skills; comfort working across the full stack from hardware abstraction to developer API
Demonstrated ability to lead technically in a remote-first, distributed environment.
Excellent cross-functional communicator, capable of working with hardware architects and product stakeholders
Bachelor's degree or higher in Computer Science or related discipline, or equivalent experience
Strong Preference For
Prior experience at an AI accelerator startup or in a semiconductor SW organisation
Background in compiler design, MLIR, or custom hardware backend development
Track record of open-source leadership or significant community contribution in ML infrastructure
Highly Competitive Salary: We are not saying our salary is a blank check, but let's just say it won't be a source of your stress
Share Option Scheme: We are all in this together! We believe in shared success while we build the Lumai of tomorrow
L&D Allowance: Stay at the forefront of your field with a €500 annual development budget
Holidays: Enjoy some deserved "me time" with 25 days paid holiday (plus bank holidays) per year
Socials: Be part of an inclusive community enjoying occasional all-company off-sites, lunches and socials
Our process is four stages. An initial conversation with our HR team to understand what you want from the role and what we want from it. Two technical sessions with various members of our engineering team. Finally, an HR-team session covering scope, terms, and any final questions. We aim to move fast on candidates we are excited about; expect roughly three to four weeks end to end.
Lumai is an equal opportunity employer. We make hiring decisions on merit, scope-fit, and the strength of the working relationship we expect to build with each hire. Applications welcome from candidates of any background. If you are not sure whether you are a fit, send a note anyway.
About Lumai
Lumai is the optical compute company building the next generation of AI infrastructure. Spun out of optics research at the University of Oxford in 2021, we compute with light instead of electrons. Our 3D optical technology carries out the matrix multiplications at the heart of AI inside beams of light travelling through free space, which lets it go beyond the limits of both silicon GPUs and integrated photonics.
In April 2026 we launched Iris Nova, the world's first optical computing system to run billion-parameter large language models in real time, using up to 90% less energy than conventional GPU-based systems. Iris Nova, the first server in the family, is now available for evaluation by hyperscalers, neoclouds, enterprises and research institutions. Aura and Tetra will follow.
Our work won the Falling Walls Award for Science Breakthrough of the Year 2025 and 'Best Overall Technology' at the OCP Future Technologies Symposium. We are headquartered in Oxford.
Why Lumai
You'll work on a new kind of computer. Optical computing for AI has been promised for decades. We have a working system running real models, and the hard part left is taking it to volume.
Your work ships. We are moving from first product to volume production, so what you build this year goes into the servers our customers run.
You'll work across disciplines. Optical engineers, machine learning researchers, and hardware and software engineers solve problems together. You will learn things that don't appear on your job description.
The work matters beyond Lumai. AI's appetite for energy is one of the defining constraints of the next decade. Our mission is sustainable intelligence at global scale: AI that is faster, cheaper to run and far less power-hungry.
You'll join early. You'll have a real say in how we build the product, the team and the way we work.
Equal Opportunity
Lumai is an equal opportunity employer. We make hiring decisions based on skills, experience and potential, and we welcome applications from people of all backgrounds. If you need an adjustment at any stage of the hiring process, let us know and we will do our best to support you.
Skills Required
- 7+ years of software engineering experience
- At least 2 years in a tech lead or senior individual contributor role
- Deep expertise in AI/ML systems (inference pipelines, model optimisation, accelerator programming)
- Strong Python skills
- Strong C/C++ skills
- Experience working and leading technically in a remote-first, distributed environment
- Excellent cross-functional communication with hardware architects and product stakeholders
- Bachelor's degree or higher in Computer Science or related discipline, or equivalent experience
- Prior experience at an AI accelerator startup or semiconductor software organisation
- Background in compiler design, MLIR, or custom hardware backend development
- Track record of open-source leadership or significant ML infrastructure community contribution
What We Do
Lumai is an optical compute company building the next generation of AI infrastructure for the inference era. By utilizing 3D optical computing, the company develops energy-efficient AI processors that surpass the limitations of silicon-based architectures, delivering significantly higher performance and lower power consumption to unlock sustainable intelligence at scale.
