Product Engineer

HartleyCo; Greater London; On-site; GBP 100,000 - 150,000; Full time

Benefits offered by this job

Equity

Private medical

Pension

30 days flexible remote work

Job summary

HartleyCo is seeking a Product Engineer for a London-on-site role. You will design and build full‑stack features and AI agents, working closely with users to understand workflows and drive rapid production delivery.

You’ll own features end‑to‑end, collaborate with AI and operations teams to ensure reliable automations, and contribute to scalable systems as usage grows, all in a fast-paced startup environment.

Qualifications

• Strong full-stack experience with modern web stacks.
• Hands-on experience building with LLMs and AI agents.
• Comfortable owning features end-to-end without detailed specs.
• Startup experience is a plus; drive and pace matter.

Responsibilities

• Collaborate with internal users to understand workflows and pain points.
• Design and build full-stack features and AI agents from idea to production.
• Work with AI and operations teams to ensure reliable and safe automations.
• Improve systems as usage grows and scale the product.

Skills

TypeScript

React

Node.js

LLMs

End-to-end ownership

Job description

Product Engineer - London (On-site) | £100,000 to £150,000 + equity | Full-time

About the company

A YC-backed AI startup that is about to close a significant Series A. They’re rebuilding a large, traditional industry that still relies on slow manual processes, and they’ve grown rapidly over the last year with a strong list of enterprise customers.

The role

This is a hands-on engineering role that sits very close to the people using the product. You’ll find where work gets stuck, build AI-powered tools and agents to fix it, and get them into production quickly. The loop between spotting a problem and shipping the fix is short, so you’ll see the impact of your work almost straight away.

What you’ll be doing

• Spending time with internal users to understand their workflows and pain points
• Designing and building full-stack features and AI agents from idea to production
• Working with the AI and operations teams to make sure automations are reliable and safe
• Improving systems as usage grows

What they’re looking for

• Strong full-stack experience, ideally TypeScript, React and Node
• Hands‑on experience building with LLMs, ideally systems that take actions rather than just answering questions
• Comfortable owning features end to end without detailed specs
• Thinks carefully about what happens when automation gets it wrong
• Startup experience is a plus. Drive and pace matter more than years of experience

What’s on offer

• £100,000 to £150,000 base plus meaningful equity
• 30 days a year working from anywhere, separate from annual leave
• Private medical, pension and a fast-track promotion path
• On site in Central London with a high-energy team