Senior AI Engineer

Role: Senior AI Engineer (x2) Location: Shoreditch, London (hybrid - 3 days per week) Salary: £80,000 - £110,000, plus benefits (below) Key Skills: Python, AI/LLMs, LangChain/LangGraph, AI Agents, AWS Industry: B2B SaaS Start-up A fast-growing B2B SaaS start-up is looking for a talented Senior AI Engineer to set up and co-lead the introduction of AI and LLM-powered capabilities across their platform. This is a rare opportunity to join at a pivotal moment and take high ownership from day one , writing production code immediately and making strategic technical decisions that shape the company’s AI roadmap. The role sits at the heart of product innovation, blending engineering, AI application, and product thinking to drive value for customers. This position is ideal for an experienced engineer who thrives on autonomy, wants to shape foundational AI capabilities, and is passionate about delivering real-world, user-facing AI features at scale. You will: Establish the AI engineering function from the ground up Build and deploy intelligent agents and scalable content generation tools Integrate LLMs and orchestrate complex workflows using state-of-the-art frameworks Collaborate closely with product and design to prototype, ship and iterate quickly Drive high-impact work in a fast-paced, high-trust environment Continuously explore and evaluate emerging LLM tools, techniques, and architectures to evolve our AI offering. Contribute to UX thinking for how AI capabilities are surfaced in the platform. What we're looking for: AI/ML or LLM-based development in a fast-paced start-up environment. Built and deployed production-grade agentic systems Hands-on experience with PydanticAI, LangChain, LangGraph, or similar agent orchestration tools. Strong understanding of LLM evaluation, prompt design, and techniques for tuning models to domain-specific tasks. Deep understanding of large language models (LLMs), including advanced concepts such as key-value (KV) caching, tool integration, and sampling strategies to optimise performance and output quality. A first-principles mindset and excitement to architect our core AI systems from scratch. Full-stack capability - you can own a feature end-to-end, from API to infrastructure to evaluation. Benefits: Equity 25 days holiday local public holidays Top-spec Apple hardware & remote-friendly setup budget Office in Shoreditch with access to a private gym Team offsites twice a year Enhanced parental leave Regular team socials