Product Engineer - Founding - AI

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

Benefits offered by this job

Meaningful equity

Job summary

Atarus is seeking a Founding AI Product Engineer to join an AI-native operating system startup focused on large-scale energy and infrastructure projects. You will own production LLM agents, multi-agent workflows, and human-in-the-loop verification systems, delivering data-heavy frontend workflows from concept to production.

The role combines full-stack engineering with sophisticated LLM systems, offering founding-level ownership and meaningful equity as the company scales with leading VC backing.

Qualifications

• 4+ years of strong software engineering experience with production experience in LLMs, agent architectures and context engineering.
• Comfort across the full stack with strong product instincts.
• Experience building data-heavy frontend products for complex professional workflows.

Responsibilities

• Own production LLM agents and multi-agent workflows.
• Develop human-in-the-loop systems for reviewing and verifying AI outputs.
• Deliver end-to-end features from problem definition to production.

Skills

LLMs production experience

Agent architectures

Context engineering

Full-stack product engineering

Job description

We’re working with a well-funded AI startup building an AI-native operating system for large-scale energy and infrastructure projects.

They’re hiring a Founding AI Product Engineer to work directly with the founders, combining full-stack product engineering with sophisticated LLM systems.

You’ll own

• Production LLM agents & multi-agent workflows
• Human-in-the-loop systems for reviewing and verifying AI outputs
• Data-heavy frontend products for complex professional workflows
• Features end-to-end — from ambiguous customer problem through to production

4+ years of strong software engineering experience, with genuine production experience across LLMs, agent architectures and context engineering. You’ll need to be comfortable across the full stack and have strong product instincts — this isn't a pure ML role.

The sweet spot

Founding-level ownership, meaningful equity, backing from leading VCs and AI investors, and the opportunity to build AI systems tackling a huge bottleneck in global energy infrastructure.