Full Stack Software Engineer (AI Systems) London | Full-time | On-site (5 days/week) £130,000 - 150,000 Equity Daily lunch & snacks provided Tech stack: Python · TypeScript · AI / Generative AI · Agentic Systems Build AI that actually does things I'm hiring a Full Stack Engineer to join a high-growth, well-funded AI start-up building production-grade conversational AI agents used by major FTSE 100 companies across healthcare, travel, and financial services. Through offering a leading conversational AI platform the company aims to empower every brand to deliver top class customer service and experience The company is valued at $1.5bn, with a live, revenue-generating product and strong enterprise adoption. You'll be joining the London engineering team at a moment of real momentum. What you'll work on You'll help design and build intelligent AI systems that don't just respond - they reason, interpret context, and take action. This role offers full ownership: Take ideas from concept → design → production Build and evolve AI agents used daily by real customers Work closely with product and customer-facing teams to understand pain points and rapidly ship improvements Contribute across the stack, from backend logic to user-facing behaviour Engineers here are trusted to experiment, ship quickly, and make decisions that have measurable, visible impact. What they're looking for Essential experience 2 years as a professional software engineer working on production systems Strong proficiency in Python and TypeScript Comfort with async workflows, error handling, and performance considerations Strong debugging instincts — you enjoy digging into logs, traces, and data to understand how systems behave A logical, curious mindset and a desire to understand how AI systems fail — and how to make them better Background Computer Science (or similar) degree from a well-regarded university Programming language experience is flexible — Python/TypeScript are core, but strong fundamentals matter more Nice to have (not required) Exposure to generative AI, agentic systems, or multimodal AI Experience with conversational platforms or enterprise-scale SaaS products Interest in observability, testing, simulation, or AI transparency tooling Curiosity about how complex systems make decisions and how to explain them clearly Why this role stands out Immediate impact : the systems you build go straight into production and are used at scale Engineering-first culture : AI behaviour is observable, testable, and versioned — not buried in opaque prompts Built for iteration : powerful tooling lets you trace decisions, inspect data inputs, and understand performance end-to-end Real momentum : strong product adoption, clear market demand, and enterprise customers relying on this tech daily Learn AI properly : this is a rare chance to step into advanced AI systems with hands-on mentorship, not hype