Senior Applied AI Engineer

We’re scaling fast with more customers, more releases, and bigger regulatory and market challenges. Expectations are rising, due diligence now means real-time insight, delivered efficiently and with impact. You won’t just be executing campaigns, closing deals, or managing numbers, you’ll be influencing strategy, optimising processes, and helping position a brand that’s setting the new standard for trust and transparency.

For people who love learning, innovating, and making an impact that matters now is the moment to be a part of Xapien.

We turn a week of analyst work into seven minutes. Getting there took a while. Getting to "trust it with a £10bn decision" is the interesting part — and where you come in.

The work

You'll own parts of the Xapien pipeline end-to-end — LLM research agents, entity resolution, report generation. Prototype, evaluate, ship, measure, improve.

Build a system optimised for accuracy, speed and cost Design evals that measure what matters, driving meaningful improvements Dig into the failures and fix them at the root Shape and ship what's next - high ownership

We use Claude Code by default and rarely write code ourselves. The craft is in careful prompting, tight loops, sharp evals, and spotting when the agent's quietly wrong.

You

Fluent in Claude Code, Codex, or similar agentic tooling. Strong numerical reasoning. Top-uni CS / maths / engineering / science, or equivalent in what you've built. Shipped production LLM systems — RAG, prompting, agents. The kind customers pay for. You've worked somewhere fast — startup or strong tech team — and make good calls on imperfect information. You know software engineering: you’ve launched systems, responded to incidents, designed for failure High-agency. You scope problems, own solutions, and help decide what we build next. Focused on real answers for real customers. Theory's a tool, not the point. Good to work with. Small team — it matters.

Here’s our promise to you:

We are going to work with you - to build a rewarding and fulfilling career with the opportunities, challenges and resources you need to do you your best work. We succeed together- you will own a meaningful part of the business through our employee shares & equity programme. Private health insurance to keep you in tip-top condition. Life Insurance – let's hope nobody ever needs this! Unlimited holidays – yes, it really is uncapped – take the time you need, when you need it. Everyone is learning, developing and challenging themselves so we have a £1k professional development fund per year if you want to learn new skills, even new things outside of work. Most importantly of all, we will work with you, to help you realise your fullest potential, always.