Senior Applied AI Engineer — Real-Time LLM Systems + Equity in London

About Us

Every business needs to know who they're really working with whether it's suppliers, investors, partners, or third parties. At Xapien, we're reinventing how organisations do that, combining speed, scale and accuracy with cutting-edge AI. Since 2018, we've grown from a deep-tech startup to a global player in AI-driven due diligence and risk intelligence. 2024 was a landmark year as we closed a $10M Series A, earned recognition in the Chartis RiskTech100® and Everest Group's Leading 50™, and expanded our products, markets and customer base. 2025 was even bigger: With new regulations, rising compliance pressure and growing reputation risks, organisations everywhere are demanding smarter, faster ways to work and they're turning to us. Customers worldwide from global law firms and private banks to universities and nonprofits rely on Xapien to turn days of manual research into trusted insights, delivered in minutes.

Our momentum so far

Customers in a diverse range of industries, with particular growth in wealth management, financial services and supply chain onboarding. Demand accelerating beyond our UK headquarters, across multiple continents with new customers in the Middle East, Asia, and Oceania.

Why this is an exciting time to join

This isn't just another job role; it's an opportunity to shape the future of the due diligence industry with a market-leading product trusted by global organisations. Whether you're in marketing, communications, sales, or finance, you'll play a critical role in driving growth, building credibility, and defining how we connect our product to a rapidly evolving market. 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 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.