Python Senior Engineer - 12 Months - London - Hybrid You will join the Recommendations team, contributing to the AI Stylist experience, an AI-powered product that combines conversational interfaces with recommendation capabilities. The work sits at the intersection of engineering and AI, focused on improving relevance, quality, and reliability in a live, customer-facing system. You will collaborate closely with engineers, data scientists, and product stakeholders to evolve the system and support its rapid growth Your responsibilities: Building and evolving AI-powered services using Python Designing and implementing evaluation frameworks for LLM-based systems Improving output quality through structured evals rather than purely code changes Applying techniques such as LLM-as-a-Judge to assess response and recommendation quality Working with non-deterministic systems and iterating based on real-world behaviour Integrating AI services into a broader platform and API ecosystem Contributing to production readiness including reliability, observability, and performance Partnering with data scientists on prompts, model usage, and evaluation strategies Essential skills/knowledge/experience: Strong Python engineering experience in production environments Experience building AI-enabled applications, particularly in recommendation or conversational systems Hands-on experience with evaluation frameworks for LLM or AI systems Clear understanding of how AI systems differ from traditiona