Lead Product Engineer / CTO

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 platformBuild backend services and APIs in PythonDesign complex SQL/PostgreSQL data modelsBuild data pipelines and retrieval systemsDevelop RAG and semantic search capabilitiesBuild production AI/LLM featuresMake architecture and infrastructure decisionsTake ambiguous problems from 0→1Establish engineering standardsHelp 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 engineeringExcellent SQL / relational database knowledgeExperience with RAG, retrieval or semantic searchExperience owning production software end-to-endComfortable working across the full stackStrong product and technical judgementComfortable solving highly ambiguous problemsStartup / scale-up experienceHigh ownership and autonomyTechnically 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 conversationShort take-home — AI use encouraged60-minute technical discussion30-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 → CTOBecome one of the most senior technical people in the businessGenuine ownership over product and architectureBuild across AI, RAG, data and backend engineeringWork directly with company leadershipHelp build the engineering team around youExisting customers with a major new product directionFlexible London / remote workingEquity 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. Apply with your CV and we'll be in touch if there's alignment