Senior AI Product Engineer

Harnham - Data and Analytics Recruitment; Greater London; Hybrid; GBP 126,000 - 154,000; Full time

Benefits offered by this job

Salary up to £140,000

Job summary

Harnham - Data and Analytics Recruitment is seeking a Senior AI Product Engineer to join London on a hybrid basis. You will be the first senior engineering hire, owning end-to-end AI product development and scaling the RAG/AI app layer.

You will work across backend, APIs, and cloud infra, with frontend as needed, driving best practices in testing, architecture and delivery. Salary up to £140,000 depending on experience.

Qualifications

• Experience delivering production LLM-enabled products.
• Strong backend expertise with full-stack capability.
• Ability to own product architecture and make independent decisions.

Responsibilities

• Build and ship AI-powered products end-to-end using LLM technologies.
• Own and scale the retrieval-augmented generation (RAG) and AI app layer.
• Develop secure, production-grade systems with guardrails, monitoring, and cost control.
• Work across backend, APIs, cloud infra, and some frontend development.
• Establish engineering best practices for testing, delivery, architecture, and code quality.

Skills

LLM-enabled products

Full-stack development

Product ownership

TypeScript

Node.js

React

PostgreSQL

AWS

API-first design

Tools

TypeScript

Node.js

React

PostgreSQL

AWS

APIs

Job description

Senior AI Product Engineer

up to £140,000
London (Hybrid)

This is a fantastic opportunity to join an early-stage AI startup as one of its first engineering hires, taking ownership of a cutting-edge behavioural AI platform that is transforming how companies understand and engage with their customers.

THE COMPANY:

Our client is developing technology that helps their clients better understand not just what customers do, but why they make decisions. Their platform combines behavioural science and AI to provide actionable customer intelligence, enabling organisations to improve marketing, communications, customer support, and engagement strategies.

THE ROLE:

You will become the first senior individual contributor engineering hire, working closely with the VP of Product Engineering to build and scale the product from the ground up.

Key responsibilities include:

• Building and shipping AI-powered products end-to-end using LLM technologies.
• Owning and scaling the retrieval-augmented generation (RAG) and AI application layer.
• Developing secure, production-grade systems including guardrails, evaluation frameworks, monitoring, caching, and token cost optimisation.
• Working across the stack, including backend services, APIs, cloud infrastructure, and selective frontend development.
• Establishing engineering best practices around testing, delivery, architecture, and code quality.

YOUR SKILLS AND EXPERIENCE:

You will bring strong capability in:

• Building and scaling production LLM-enabled products from 0-to-1.
• Full-stack software engineering with strong backend expertise.
• Product ownership, architecture, and independent decision-making.
• Modern technologies including TypeScript, Node.js, React, PostgreSQL, AWS, and API-first architectures.
• LLM evaluation, token optimisation, cost management, monitoring, and deployment best practices.

THE BENEFITS:

You will receive a salary of up to £140,000 depending on experience.