Full Stack Developer jobs in United Kingdom

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

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 in a live environment.

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.

You’ll help design and build intelligent AI systems that don’t just respond – they reason, interpret context, and take action.

• 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.

• 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

• Computer Science (or similar) degree from a well‑regarded university
• Programming language experience is flexible – Python / TypeScript are core, but strong fundamentals matter more

• 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

• 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