Senior Applied AI Engineer in City of London

We’re working with an exciting high-growth AI business that is building technology to transform how organisations research, assess and manage risk. The company has developed a sophisticated AI-driven platform that combines LLMs, unstructured data and intelligent automation to deliver high-quality insights in a high-stakes environment. With significant growth and increasing demand internationally, they’re now looking for a Senior Applied AI Engineer to help take their AI systems to the next level. This is a genuinely hands-on engineering role for someone who enjoys taking AI from prototype through to reliable production systems.

The Role

• Building and improving production LLM-driven systems, including RAG and agentic workflows.
• Developing high-quality, reliable and well-tested Python code.
• Designing and implementing evaluations (evals) that genuinely measure whether AI systems are improving.
• Investigating and resolving real-world production failures and understanding their root causes.
• Improving the accuracy, cost and latency of AI systems.
• Working closely with Product to shape and deliver new AI capabilities.
• Architecting and maintaining scalable microservice-based systems.
• Experimenting with LLMs, prompting and related technologies to solve complex problems.
• Supporting and mentoring more junior engineers.
• Working in an environment where AI coding tools and agentic development are heavily embedded into the engineering workflow.

What We're Looking For

• 4+ years' experience building production software.
• 2+ years' experience building production LLM applications.
• Strong hands-on experience with Python.
• Experience building RAG systems, LLM applications and/or AI agents.
• A strong understanding of how LLM systems work, including areas such as embeddings, prompting and model parameters.
• Experience designing AI evaluations and measuring the quality of LLM outputs.
• A strong understanding of software engineering principles, testing and production reliability.
• Experience working in a fast-moving environment, ideally within a startup or scale-up.
• Excellent communication skills and the ability to explain technical concepts clearly.
• A product-focused mindset and the ability to make sensible engineering decisions in ambiguous environments.

Desirable Experience

• LLM fine-tuning
• Agentic AI systems
• Microservice architecture
• Go
• Deep learning / traditional machine learning
• AI coding and agentic development tools such as Claude Code, Codex or similar

What This Role Isn't

This isn't an academic research position and you won't be expected to train foundation models. We’re particularly interested in engineers who have actually shipped AI products into production and understand the challenges that come with reliability, accuracy, cost, latency and real users. You should be comfortable getting stuck into problems, experimenting quickly, understanding when an AI system isn't performing as expected and then engineering a solution.

Why Join?

• £110,000–£140,000 salary
• Equity package
• Hybrid working – 2 days per week in London
• Opportunity to work on genuinely challenging Applied AI problems
• Significant influence over the development of the company's AI platform
• Work closely with senior technical and product leadership
• £1,000 annual professional development budget
• Private healthcare
• Life insurance
• Unlimited holiday

The business has already secured significant investment and is experiencing strong international growth, making this an exciting time to join and have a genuine impact on the direction of the technology.