Lead Product Engineer → CTO - Python, SQL, RAG, AWS, Typescript - AI and Data Infrastructure, Start - UP - Technical Ownership, 0→1 - UK - Base £80 - 100k + Equity

Lead Product Engineer → CTO | Python, SQL, RAG, AWS, TypeScript | AI & Data Infrastructure, Start-up | Technical Ownership, 0→1 | UK remote | Base £80-100K + Equity 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. The Role – Lead Product Engineer → CTO | Python, SQL, RAG, AWS, TypeScript | AI & Data Infrastructure, Start-up | Technical Ownership, 0→1 | UK remote | Base £80-100K + Equity 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
• Design complex SQL/PostgreSQL data models
• 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
• Establish engineering standards
• Help build and technically lead the engineering team Tech Stack - Lead Product Engineer → CTO | Python, SQL, RAG, AWS, TypeScript | AI & Data Infrastructure, Start-up | Technical Ownership, 0→1 | UK remote | Base £80-100K + Equity Python | SQL | PostgreSQL | TypeScript | AWS | RAG | LLMs | APIs | Data Pipelines 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
• Strong Python backend engineering
• 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
• Short take-home — AI use encouraged
• 60-minute technical discussion
• 30-minute culture conversation Why Join? - Lead Product Engineer → CTO | Python, SQL, RAG, AWS, TypeScript | AI & Data Infrastructure, Start-up | Technical Ownership, 0→1 | UK remote | Base £80-100K + Equity
• 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 Apply with your CV and we'll be in touch if there's alignment