Lead Engineer - AI Scale-Up - Node/ AWS/ LLM/ RAG/ AI - Up to £110k

A fast‐growing Series A AI start‐up is building production‐grade AI systems for UK financial services are hiring a Lead Software Engineer (Node.js) to set technical direction, own architecture, and lead hands‐on delivery of AI‐powered products.

This is a senior individual contributor role (no management) - You’ll act as the technical co‐lead alongside an Engineering Manager, owning engineering quality, architectural decisions, and complex problem‐solving in a regulated environment.

There is tons of autonomy and a real chance for you to really make a big impact and put your mark on the product & culture!

They received Series A funding and are scaling quite heavily as a business to continue to grow their product line (team size is 100)

What you’ll do

• Own technical direction for your squad: architecture, ADRs, standards, and technical risk
• Design and deliver LLM‐powered features: workflows, RAG pipelines, prompt engineering, and agentic execution
• Lead adoption of an AI & Agentic Platform (LLM routing, guardrails, observability, evaluation)
• Build and ship production‐grade Node.js services on AWS (serverless, Lambda, DynamoDB, event‐driven systems)
• Set the quality bar: code reviews, test coverage, security‐by‐design, performance, reliability
• Influence cross‐squad architecture and contribute to architecture review governance
• Champion compliant‐by‐design engineering in an FCA‐regulated context (auditability, traceability)

What they’re looking for

• 10+ years of software engineering experience, including 3+ years in production AI systems
• Strong Node.js expertise (this role is Node‐first)
• Hands‐on experience with LLMs: prompt engineering, RAG, evaluation, agentic patterns
• Cloud‐native AWS experience (Lambda, DynamoDB, S3, event‐driven architectures)
• Proven ability to set technical direction, mentor engineers, and influence architecture beyond your team
• Strong written communication: clear ADRs and design documentation

Nice to have

• Background in FinTech or regulated financial services
• Experience with model routing / abstraction layers
• AI observability: cost monitoring, drift detection, safety evaluation
• Familiarity with ISO 27001 / SOC 2 or compliance‐heavy environments

Why this role

• Real AI in production
• High‐impact technical ownership in a scaling AI start‐up
• Fully remote, UK‐based role
• Complex, meaningful problems at the intersection of AI, software engineering, and regulation