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.
Lumai's hardware needs software that runs reliably at the lowest levels of the stack. As our Junior Embedded Engineer, you will build the firmware, drivers, and RTOS-based control software that bring our AI accelerator to life — from initial power-on through to stable, performant operation in production systems.
Implement and integrate RTOS tasks and inter-process communication mechanisms for accelerator management software
Contribute to BSP bring-up activities: validating peripheral drivers, configuring boot loaders, and supporting first-boot debugging sessions
Write unit and integration tests for firmware modules; maintain embedded CI pipelines
Support hardware debug sessions using JTAG, GDB, and benchtop instrumentation
Document firmware interfaces, register maps, and bring-up procedures for internal use
Collaborate with the Senior Embedded Engineer and HW teams on new hardware revision planning
Must-Have
3+ years of embedded C/C++ experience in a hardware product environment
Working knowledge of at least one RTOS (FreeRTOS, Zephyr, or similar) in a production context
Experience with BSP or board bring-up activities, including boot loader configuration
Comfort with hardware debugging tools (JTAG, oscilloscopes, serial consoles)
Familiarity with Linux kernel concepts and basic driver development
Bachelor's degree or higher in Electrical Engineering, Computer Engineering, or equivalent
Strong Preference For
Experience with DMA controllers or cache coherency management
Background in safety-critical or automotive embedded software (MISRA C, ISO 26262)
Exposure to Python-based test automation for hardware-in-the-loop testing
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
Pension Scheme: Plan for retirement with AVIVA
Private Health Insurance: We firmly believe that you come first, and a happy you is a healthy you! Look after yourself and your loved ones with AXA
Cycle to Work: Spread the cost of a bike, a bike and accessories or just accessories and save on tax
L&D Allowance: Stay at the forefront of your field with a £500 annual development budget
Subsidised On-site Lunches: Enjoy on-site healthy meals at half the price, as Lumai covers 50% of the cost
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.
Skills Required
- 3+ years of embedded C/C++ experience in a hardware product environment
- Working knowledge of at least one RTOS (FreeRTOS, Zephyr, or similar) in a production context
- Experience with BSP or board bring-up activities, including boot loader configuration
- Comfort with hardware debugging tools (JTAG, oscilloscopes, serial consoles)
- Familiarity with Linux kernel concepts and basic driver development
- Bachelor's degree or higher in Electrical Engineering, Computer Engineering, or equivalent
- Experience with DMA controllers or cache coherency management
- Background in safety-critical or automotive embedded software (MISRA C, ISO 26262)
- Exposure to Python-based test automation for hardware-in-the-loop testing
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.
