Senior AI Software Engineer

Senior AI Software Engineer

London (Hybrid, 3 days per week)

Up to £140,000 + Equity

We're partnered with a fast-growing AI start-up building cutting-edge behavioural intelligence technology for the financial services sector. Backed by an exceptional leadership team and industry experts, they're developing a platform that helps organisations better understand client behaviour through advanced AI and large language models.

As their first senior individual contributor engineering hire, you'll play a critical role in shaping both the product and engineering culture from the ground up.

The Opportunity

This is a true 0-to-1 product engineering role. You'll work closely with senior leadership to build and scale a greenfield product, taking ownership across the full stack while driving the architecture and evolution of production-grade AI systems.

You'll have significant influence over technical direction, engineering standards, product decisions and future hiring as the team grows.

What You'll Be Doing

• Building and shipping customer-facing product features end-to-end

• Developing and scaling production LLM applications

• Owning RAG pipelines and AI application architecture

• Implementing guardrails, evaluations, caching and model routing strategies

• Working across TypeScript, React, Node.js, PostgreSQL and AWS (Open to different technology backgrounds!)

• Building API-first services for enterprise customers

• Establishing engineering best practices around testing, deployment and code quality

• Collaborating directly with product and leadership stakeholders to influence roadmap and delivery priorities

What We're Looking For

• Experience building and scaling production LLM-powered applications

• Strong full-stack engineering background

• Experience delivering secure, reliable and scalable systems

• Comfortable working across multiple technologies and learning new stacks quickly

• Experience with React and modern web applications

• Product-minded approach with the ability to operate autonomously

• Passion for building in an early-stage, high-growth environment

• Experience within regulated industries or financial services is beneficial but not essential

Why Join?

• Up to £140,000 base salary

• Meaningful equity package

• Opportunity to become the first senior engineering hire

• Direct impact on architecture, product and company direction

• Work alongside talent from leading technology and AI organisations

• Greenfield product with genuine product ownership

• Hybrid working in Central London

• 25 days holiday plus additional benefit