Lead Product Engineer → CTO | Python, SQL, RAG, AWS, TypeScript | AI & Data Infrastructure, Start-up | Technical Ownership, 0→1 | UK remote | Base £80-100K + Equity

Owen Thomas | B Corp™; Greater London; Hybrid; GBP 120,000 - 190,000; Full time

Benefits offered by this job

Equity

Flexible London/remote working

Job summary

Owen Thomas | B Corp™ partners with an early-stage AI company building technology that helps organisations make better decisions from complex, fast-changing information. Data is the product and the frontend is the wrapper.

They are entering a growth phase and are hiring senior engineers to own the platform. You'll be highly hands-on across Python, data, RAG, AI and infrastructure, shaping what gets built and how the engineering function evolves.

Qualifications

• Excellent SQL / relational database knowledge.
• Experience with RAG, retrieval or semantic search.
• Experience owning production software end-to-end.
• Comfortable working across the full stack.
• Strong product and technical judgement.
• Startup / scale-up experience.
• High ownership and autonomy.
• Technically strong while commercially minded.

Responsibilities

• Own and evolve the core AI & data platform.
• Build backend services and APIs in Python.
• Build data pipelines and retrieval systems.
• Develop RAG and semantic search capabilities.
• Build production AI/LLM features.
• Make architecture and infrastructure decisions.
• Take ambiguous problems from 0→1.
• Help build and technically lead the engineering team.

Skills

SQL

RAG search

Semantic search

End-to-end production

Full stack

Technical judgement

Startup experience

Autonomy

Tools

None

Job description

The Company

We're partnering with an early-stage AI company building technology that helps organisations make better decisions from complex, fast-changing information.

At the heart of the business is a unique and growing data asset.

They're building an intelligence layer around this data — combining software engineering, data infrastructure, retrieval and AI to make it searchable, usable and trustworthy.

Data is the product. The frontend is the wrapper.

They already have customers and are now entering their next stage of growth, rebuilding the engineering team around a small number of exceptional hires.

This is a rare opportunity to join as one of the most senior technical people in the business and take significant ownership of the platform.

You'll be highly hands-on across Python, data, RAG, AI and infrastructure, while helping determine what gets built, how it's built and how the engineering function evolves.

You'll work directly with leadership, taking ambiguous problems and turning them into production software.

As the company scales, there is potential for this person to grow into broader technology leadership and ultimately a CTO-level role.

What You'll Be Doing

• Own and evolve the core AI & data platform


• Build backend services and APIs in Python


• Build data pipelines and retrieval systems


• Develop RAG and semantic search capabilities


• Build production AI/LLM features


• Make architecture and infrastructure decisions


• Take ambiguous problems from 0→1


• Help build and technically lead the engineering team

AI is deeply embedded into how the team builds. Engineers are encouraged to use AI coding tools extensively, while remaining responsible for understanding, testing and owning what they ship.

What They're Looking For

• Excellent SQL / relational database knowledge


• Experience with RAG, retrieval or semantic search


• Experience owning production software end-to-end


• Comfortable working across the full stack


• Strong product and technical judgement


• Comfortable solving highly ambiguous problems


• Startup / scale-up experience


• High ownership and autonomy


• Technically strong while commercially minded

You don't need to already be a Tech Lead.

They're more interested in what you've owned, the decisions you've made and whether you're capable of becoming the person others rely on for technical judgement.

Interview Process

• Initial conversation


• 60-minute technical discussion


• Potential path from Lead Product Engineer → CTO


• Become one of the most senior technical people in the business


• Genuine ownership over product and architecture


• Build across AI, RAG, data and backend engineering


• Work directly with company leadership


• Help build the engineering team around you


• Existing customers with a major new product direction


• Flexible London / remote working


• Equity alongside salary

If you're a senior Product Engineer who wants more than another IC role — and wants the opportunity to build the product, shape the technology and potentially grow into leading the entire engineering function — we'd love to hear from you.