Product AI Engineer

numi; Greater London; On-site; GBP 70,000 - 100,000; Full time

Job summary

numi, an early-stage AI company building agents for the infrastructure sector, seeks a software engineer to own end-to-end features on a modern TypeScript stack. You’ll ship frontend, backend, and integrations with real ownership from problem to production.

Work includes React and Node, APIs, data models, and LLM-backed features. This in-person role is based in central London and offers close collaboration with the VP Engineering to shape product and tech direction as the company scales.

Qualifications

• 3+ years of software engineering experience.
• Strong TypeScript—this one's non-negotiable.
• Track record of shipping real products across frontend and backend.
• Hands-on experience with LLMs, agents or AI APIs.
• Exceptional diligence and genuine attention to detail.
• High agency, ownership, and comfort with ambiguity.

Responsibilities

• Build and ship across a modern TypeScript stack (frontend, backend, integrations).
• Develop APIs, data models and integrations; wire platform into customer systems.
• Build LLM-backed features and AI tools; prompt engineering and tool use.

Skills

TypeScript

Frontend development

Backend development

LLMs/APIs

Ownership

Ambiguity tolerance

Tools

React

Node.js

APIs

Job description

We're partnering with a well-backed, early-stage AI company building AI agents for one of the world's largest and least-disrupted industries: the firms that design, build and maintain physical infrastructure. Think agents and software that plug straight into the systems some of the biggest engineering consultancies on the planet already run on — and take real operational work off their hands.

They're early, moving fast, and have a genuinely generational shot at defining how this industry works with AI. It's a small, high-performance team: direct, quality-obsessed, and happiest solving hard problems together.

This role sits alongside the VP Engineering, on the core product.

What you'll own

You'll build and ship across a modern TypeScript stack — frontend, backend, and the integrations that wire the platform into customer systems. Real end-to-end ownership: understand the problem, decide how to solve it, ship it, and make sure it actually works in the wild.

Day to day that looks like shipping product features across React and Node, developing APIs, data models and integrations, and building LLM-backed features — prompting, tool use, the lot. You'll turn ambiguous problems into simple working solutions, use AI heavily in how you build, find and fix problems before anyone asks, and own your work from first sketch to production.

What you'll bring

• 3+ years' software engineering experience
• Strong TypeScript — this one's non-negotiable
• A track record of shipping real products across frontend and backend
• Hands-on experience with LLMs, agents or AI APIs
• Exceptional diligence and genuine attention to detail
• High agency, strong ownership, and real comfort with ambiguity
• Sharp product judgement
• Startup experience is a strong advantage.

What's on offer

• Direct exposure to the VP Engineering
• Real ownership of meaningful parts of the product
• A seat that shapes both product and technical direction as the company scales

Location: Office-first, central London (Farringdon). This is an in-person role for someone who wants to build shoulder-to-shoulder with a high-performance team.