Senior Applied AI Engineer

AI Engineer (LLM Systems) | Series A AI Scale-Up |London (Hybrid) | 100-130k + equity I’m working with a fast-growing UK AI scale-up whose product automates complex research that used to take skilled specialists days. Its customers include banks, law firms and other organisations where a wrong answer has real consequences. The product is already fast. The next challenge is making it accurate enough to be trusted with the biggest decisions those customers make, and that’s where this role comes in. The role You’ll take end-to-end ownership of core parts of the AI platform, including LLM research agents, data matching and automated report generation. You’ll also: - Prototype, evaluate, ship, measure and improve - Balance accuracy, speed and cost across production systems - Design evals that drive meaningful improvements - Trace failures back to their root cause and fix them properly - Help decide what the team builds next This is an agent-first engineering team, so most code is written through agentic tools rather than by hand. The skill lies in precise prompting, tight feedback loops, strong evals and spotting when an agent is quietly getting things wrong. What you’ll bring - Fluency with Claude Code, Codex or similar agentic tools - Experience shipping production LLM systems that customers pay for, such as RAG, agents and prompt-driven products - Strong numerical reasoning, with a degree in CS, maths, engineering or science from a leading university, or equivalent experience - Solid software engineering experience, including launching systems, handling incidents and designing for failure - A background in a startup or strong tech team, making good decisions on imperfect information - High agency and a practical focus on solving real customer problems - A collaborative approach, as this is a small team where working well together matters What’s on offer - Meaningful equity - Private health insurance and life insurance - Uncapped holiday - An annual personal development budget If you want real ownership of LLM systems where accuracy matters, get in touch for a confidential chat. I can share the company name and full details directly.