AI/ML Engineer

Harnham - Data & Analytics Recruitment; City Of London; Hybrid; GBP 144,000 - 176,000; Full time

Benefits offered by this job

Salary up to £130,000

Job summary

Harnham is seeking an AI/ML Engineer in London’s King's Cross (hybrid, three days on site) to help design, build and operate production-grade AI systems solving real-world problems.

You will work on agentic AI, retrieval systems and enterprise-scale LLM applications, influencing technology decisions, product direction, and mentoring engineers to raise the bar across the library and lifecycle. This is a fast-growing, well-funded AI business valuing ownership and technical excellence.

Qualifications

• Strong Python software engineering expertise.
• Commercial experience developing and deploying LLM or machine learning systems.
• Hands-on experience with LangGraph, LangChain or similar agent orchestration frameworks.
• Strong RAG experience, including embeddings, chunking strategies, vector databases and retrieval evaluation.
• Understanding of graph-based retrieval approaches or graph data modelling principles.
• Experience with evaluation-led AI development, testing frameworks and regression controls.
• Regular use of AI-assisted development tools such as Cursor, Claude Code or similar.
• Ability to balance model performance, reliability, security and operating costs in production systems.

Responsibilities

• Design, build and operate LLM-powered systems at scale.
• Develop multi-step AI agent workflows and retrieval pipelines.
• Implement evaluation frameworks and monitoring for AI apps.
• Collaborate with leadership to shape technical direction and best practices.
• Mentor engineers to raise engineering standards across AI initiatives.

Skills

Python

LLM systems

LangGraph/LangChain

RAG

Graph retrieval

Evaluation frameworks

Cursor/Claude Code

Performance vs cost

Tools

LangGraph

LangChain

Weaviate

pgvector

Neo4j

Job description

AI/ML Engineer

Up to £160,000

King's Cross, London (3 days a week)

This is an opportunity to join a well-funded AI business at a pivotal stage of growth, building production-grade AI systems that solve complex, real-world problems. You'll work on agentic AI, retrieval systems, evaluation frameworks and enterprise-scale LLM applications, with the chance to influence both technology decisions and product direction.

THE COMPANY

They are an ambitious technology business developing an AI-powered platform that helps investment professionals access information, automate complex workflows and make better decisions at scale. Their platform combines proprietary data, external sources and advanced AI capabilities within a secure enterprise environment.

Backed by an established organisation with deep domain expertise and a strong client network, they offer the agility of a startup alongside the stability and resources of a proven business. The engineering team is being built with a strong emphasis on ownership, collaboration and technical excellence.

THE ROLE

As a AI/ML Engineer, you will help design, build and operate the LLM-powered systems at the core of the platform, taking AI products from experimentation to reliable production deployment.

Specifically, you can expect to be involved in the following:

• Building multi-step AI agent workflows using modern orchestration frameworks
• Developing production-scale retrieval augmented generation (RAG) systems
• Creating evaluation frameworks, testing infrastructure and monitoring capabilities for AI applications
• Designing retrieval pipelines including embeddings, vector search, reranking and knowledge retrieval
• Working with graph-based retrieval and data modelling approaches
• Optimising AI systems for accuracy, latency, scalability and cost efficiency
• Integrating leading foundation models into production environments
• Collaborating closely with engineering leadership to shape technical direction
• Mentoring engineers and helping establish best practices for AI development at Lead level
• Contributing across the full software development lifecycle using Python and cloud-based infrastructure

SKILLS AND EXPERIENCE

The successful AI/ML Engineer will have the following skills and experience:

• Strong Python software engineering expertise
• Commercial experience developing and deploying LLM or machine learning systems
• Hands-on experience with LangGraph, LangChain or similar agent orchestration frameworks
• Strong RAG experience, including embeddings, chunking strategies, vector databases and retrieval evaluation
• Understanding of graph-based retrieval approaches or graph data modelling principles
• Experience with evaluation-led AI development, testing frameworks and regression controls
• Regular use of AI-assisted development tools such as Cursor, Claude Code or similar
• Ability to balance model performance, reliability, security and operating costs in production systems

Desirable skills include:

• Qdrant, Weaviate or pgvector
• Neo4j, GraphRAG and Cypher
• MCP server development
• LangSmith, LangFuse or similar observability platforms
• Fine-tuning, embedding model selection or open-weight model deployment
• Experience working with complex document-heavy environments

BENEFITS

The successful AI/ML Engineer will receive the following benefits:

• Salary up to £130,000 - depending on experience