Senior Python Engineer - Contract - Outside IR35

We are hiring a Senior AI Engineer to join a team responsible for recommendation systems across web and mobile, working on a key AI-driven product, the AI Stylist.

This is a production-focused role. The AI Stylist is already live to customers and expected to scale significantly, with a large backlog of enhancements and increasing demand.

This is a hybrid position where 3 days per week are expected onsite in central London.

About The Role 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.

What You’ll Be Doing

• 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

Requirements What We’re Looking For Core 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 traditional deterministic systems
• Ability to design meaningful evals and improve system quality over time
• Experience working in cross-functional teams with engineering, data, and product

Nice to have

• Experience with Azure AI services or similar platforms
• Familiarity with OpenAI or similar SDKs
• Exposure to infrastructure and distributed systems
• Experience with tools such as Terraform or Kafka

Benefits Competitive day rate