Senior Generative AI Engineer

United States Digital Space LLC; Greater London; Hybrid; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Competitive salary

Equity scheme

25 days holiday

Flexible working (London office 2 days

Private medical insurance

Pension scheme

Enhanced family leave

Cycle to work scheme

Nursery salary sacrifice

1 paid volunteering day a year

Job summary

Motorway is seeking a Senior GenAI Engineer to build AI applications and agentic workflows across the GenAI stack. You will own AI features from problem framing to production, including retrieval, evaluation, and monitoring, with emphasis on reliability and safety.

You will work hands-on with Python, SQL, LLMs, and cloud tech (AWS/GCP), shaping real seller and dealer experiences on the Motorway platform. The role offers hybrid working with two days per week in London.

Qualifications

• : shipped AI/ML systems that real users depend on
• : production-grade systems
• : strong production focus with reliability
• : experience with evaluation and safety of AI features

Responsibilities

• Own AI features end to end from problem to production system
• Build retrieval and data foundations for AI features
• Design evaluation and monitoring for quality and safety
• Develop AI applications and agents using LLMs, orchestration, APIs and data systems
• Make model and cost decisions and document reasoning
• Prototype quickly and extract reusable patterns for the team
• Raise quality through code reviews and design feedback
• Translate model behaviour into business impact

Skills

Python

SQL

CI/CD

Observability

MLOps

LLM APIs

Vector Stores

Agents & Tools

Tools

AWS

GCP

Job description

About MotorwayMotorway is the UK's largest online car-selling platform. We connect private sellers directly with over 8,000 dealers nationwide. Our online platform helps sellers achieve great prices for their cars while giving dealers fast, reliable access to the stock they want for their dealerships. Founded in 2017, our award-winning, technology-led approach has redefined the experience of selling a car. the company is backed by some of the world’s leading technology investors, having raised £143 million in Series C funding.

This is a unique opportunity to join a fast-growing scale-up at a crucial phase of growth and help change an industry for the better.

About the teamGenAI Engineering sits within the company's Data and AI function, alongside Machine Learning and the Machine Learning Data Platform. We own the AI features that shape how buyers and sellers experience the marketplace, from agentic workflows in the customer journey to LLM-powered tooling for our dealer network.

What we build goes into the hands of real sellers and thousands of verified dealers, usually within weeks. When it works, someone sells their car more easily. When it doesn't, we hear about it. That feedback loop is short, and it shapes how we work. We have a track record of successful deployments and a strong reputation as a result.

About the roleWe're looking for a Senior GenAI Engineer to build AI applications and agentic workflows for the company, taking them from rapid prototype through to production-grade systems that deliver measurable value.

You'll take a problem that isn't fully defined yet and see it through to a reliable system running in production: the prompting, the retrieval, the agent design, the evals, the guardrails, the monitoring. You own that whole stack. There's no separate team who "productionises" your work later.

Most of what makes a GenAI feature good sits around the model rather than in it. The prompting is rarely the hard part. Retrieval quality is, and so is the data feeding it, evaluation you can trust, sensible behaviour when things fail, and getting it live and keeping it there. If that's the work you want to do, we're not precious about the route you took to get here. Some of us came through data science and machine learning and deliberately built up our software engineering; others came the other way.

In this role, you will:

• Own AI features end to end, from an ambiguous problem through to a reliable, observable system that real customers depend on.

• Build the retrieval and data foundations these features stand on, and treat retrieval quality as a first-class engineering problem rather than a tuning exercise.

• Design evaluation and monitoring approaches that make quality, reliability and safety measurable rather than assumed.

• Build AI applications and agents using LLMs, orchestration, APIs and data systems, applying solid production software practices throughout.

• Make the calls on models, cost and latency that shape what a feature costs us to run, and document the reasoning so others can follow it.

• Prototype quickly, work out what is reusable, and harden the patterns that work into components the rest of the team adopts.

• Raise the quality of the work around you through code review, design feedback and the standards you set by example.

• Represent your technical decisions directly to product managers and stakeholders, translating model behaviour into business consequence.

About you

• You've shipped AI or ML systems that real users depend on, and you've stayed close enough to production to know how they behave when they break.

• Strong Python, and SQL you genuinely use. A lot of this work is data work: assembling grounding data, building golden datasets, and digging into why something failed.

• You've invested deliberately in your software engineering craft: testing, error handling, CI/CD, observability, and the MLOps practices that keep things healthy once they're live.

• You're hands-on across the GenAI stack: LLM APIs, retrieval and vector stores, agents with tool use, and structured outputs, running on cloud infrastructure (we use AWS and GCP).

• You have a real point of view on evaluation, most likely because you've been caught out by a system that looked fine and wasn't.

• You can reason about how models fail, including hallucination and prompt injection, and what that means for someone who trusts the output.

• You know when to reach for a model, when something simpler will do, and when to stop.

• You're a constructive reviewer, and colleagues are better off for having worked alongside you.

You could be a great fit if

• You're curious about how things actually work, and you follow that curiosity past the first plausible answer.

• You're drawn to problems where the right approach isn't obvious yet.

• You're honest about the limits of what you know and pull people in early rather than late.

• You take responsibility for what you ship, watch how it behaves, and fix it when it breaks.

• You get satisfaction from the unglamorous work that makes an AI feature actually good, not just the part that demos well.

• You can disagree well, and commit once a decision is made.

Benefits

• Competitive salary

• Equity scheme - we all share in the company's success

• 25 days holiday

• Flexible working (2 days a week in our London office, with socials and snacks galore)

• Private medical insurance via BUPA

• Life assurance

• Pension scheme (we contribute 5%)

• Enhanced family leave (e.g. 26 weeks full pay for maternity or adoption)

• 24/7 Employee Assistance Programme

• EV leasing scheme

• Cycle to work scheme

• Nursery salary sacrifice scheme

• 1 paid volunteering day a year

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