Senior ML Runtime Engineer
Not disclosed
Salary
Not disclosed by employer
£41,700
Going rate
Skilled Worker going rate
This role may qualify for a Skilled Worker visa
SOC 5242 is an eligible occupation, but we classified this role with low confidence (34% match). If the code is right — and Fractile Ltd is a licensed sponsor — it should qualify, but double-check the occupation eligibility rules against the actual role.
About the role
ML Runtime Engineer (Mid-Level and Senior)
Fractile · London or Bristol · Full-time · Hybrid
About Fractile
We’re taking a revolutionary approach to computing — building AI acceleration hardware that runs the world’s largest language models 100× faster than existing systems. Our team works at the cutting edge of both hardware and software AI development, and we’re growing fast.
If you want your work to have a direct, meaningful impact on how AI runs at scale, you’ll fit right in.
The Role
We’re looking for a Senior ML Runtime Engineer to help us integrate Fractile’s AI accelerators with the latest inference frameworks and build the runtime stack that makes them fly. You’ll work on genuinely hard problems — KV cache management, scalable multi-user inference, and the internals of transformer model execution — alongside a collaborative team that values curiosity and rigour equally.
This is a hybrid role, with offices in London and Bristol — your choice of base.
What You’ll Do
- Integrate Fractile’s AI acceleration hardware with leading inference engines including vLLM and SGLang
- Research KV cache management technologies (including paged attention) and build proof-of-concept implementations tailored to our hardware
- Work closely with the runtime team to design and build a scalable, bare-bones reference inference engine
- Focus primarily on the transformer ML architecture
- Share your expertise to help shape the direction of our runtime stack
What We’re Looking For
We care most about depth of knowledge and a genuine interest in the problem space. You’ll be a strong fit if you have:
- Solid experience with ML inference at scale, including multi-user serving
- A deep understanding of paged attention and inference engines such as vLLM
- Familiarity with key components of the ML software ecosystem
- Strong software engineering skills and an instinct for clean, maintainable systems
Bonus Points
These aren’t requirements, but they’d make you stand out:
- Experience with Rust
- Having built your own inference engine from scratch
- A degree in Computer Science or a related field
Why Fractile
- Work on one of the most technically ambitious projects in AI infrastructure
- A small, expert team where your contributions are visible and valued
- Hybrid working — split your time between home and our London or Bristol office
- Competitive salary and equity
- A culture that values learning, directness, and collaboration
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.
This description is the source posting as it read when we added it. We are not affiliated with Fractile Ltd, so check their own site for the current details.
Where this offer sits in the market
SOC 5242 · UK · ONS ASHE 2025 · ~24k in sampleSimilar sponsored roles
See all jobsNo close matches live right now.
Browse more sponsored jobs at Fractile LtdAbout sponsorship for this role
Does this job guarantee visa sponsorship?
Not necessarily. Fractile Ltd holds a sponsor licence, but sponsorship for a specific hire is always the employer's decision. Be upfront in your application that you'll require it.
What salary is needed for this role to be eligible?
The offer must clear both the general threshold and the SOC 5242 going rate of £41,700. New-entrant and shortage discounts can lower it.