AI Engineer (up to £300k)

Dex; Greater London; On-site; GBP 90,000 - 130,000; Full time

Job summary

Dex in London is seeking a top-tier AI engineer to join a lean team building an Excel AI add-in and beyond. You will own evaluation pipelines, data collection, SFT and RL, shaping the AI agent's harness, tools, and context.

This is a hands-on, in-person role at our Hoxton office with high ownership and potential pathway to technical leadership.

Qualifications

• Demonstrable evidence of being a top-centile engineer.
• Hands-on experience building your own AI agents.
• Exceptional agency and determination to drive complex projects to completion.
• Ability to work 5 days a week, in person, from our Hoxton, London office.

Responsibilities

• Ship high-quality code at speed using AI tools and models.
• Refine the AI agent's harness, tools, and context optimization.
• Own end-to-end evaluation pipelines, data collection, SFT and RL.
• Collaborate with design to ensure intuitive and polished features.
• Grow into a technical leader with ownership of parts of the AI roadmap.

Skills

Top-centile engineer

AI agents

Data collection

SFT/RL

Tools

AI toolchains

Harness & context optimization

Job description

This role is with one of Dex's trusted partner companies. We work closely with their teams to truly understand their culture, goals, and what they're looking for, so we can match you with the right opportunity and give you context about the role before you commit to a process. Dex is an AI recruiter agent that helps you run your job search. Tell Dex your stack, seniority, and what you want to build. We will manage your applications and surface other opportunities that are a fit.

The role

Businesses make their biggest decisions on broken tools. We're fixing that, starting with financial modeling – the worst-tooled form of programming. Our AI add-in for Excel is just the beginning; the long-term vision is an AI operating system for the entire strategic decision lifecycle, a $100bn+ opportunity. We're a small, formidable engineering team, with backgrounds from top-tier institutions. This isn't a 'vibe coding' role. You'll join a lean team, focused on making our core AI agent smarter. That means improving its harness, tools, and context optimization. You'll own evaluation pipelines, data collection, SFT, and RL, with a clear path to technical leadership. Expect high ownership, deep technical problems, and a 5-day-a-week commitment in our London office.

The work

• Ship high-quality code at speed, leveraging the latest AI tools and models. AI isn't optional here.
• Enhance our AI agent's intelligence by refining its harness, tools, and context optimization.
• Own the full lifecycle of evaluation pipelines, data collection, Supervised Fine-Tuning (SFT), and Reinforcement Learning (RL).
• Collaborate closely with design to ensure every feature is intuitive and polished.
• Grow into a technical leader, taking ownership of significant parts of our AI roadmap.

What You Bring

• Demonstrable evidence of being a top-centile engineer. No compromises.
• Hands-on experience building your own AI agents, utilizing concepts like MCP, skills, and hooks.
• Exceptional agency and determination to drive complex projects to completion.
• Ability to work 5 days a week, in person, from our Hoxton, London office.