AI Engineer

The Portfolio Group; City Of London; On-site; GBP 90,000 - 130,000; Full time

Job summary

The Portfolio Group is seeking a Senior AI Engineer to lead hands-on development of sophisticated AI solutions with a focus on production engineering, retrieval performance, evaluation and scalable architecture. You will design and implement production-grade RAG pipelines and intelligent search, leveraging LangChain, LangGraph and LlamaIndex.

You will evaluate LLM outputs, drive robust experimentation, and own architectural decisions while mentoring other engineers.

Qualifications

• Experience deploying AI/ML in production environments.
• Strong Python engineering skills.
• Experience with RAG, embeddings and vector search.
• Ability to own technical decisions and mentor others.

Responsibilities

• Design production-grade RAG pipelines and intelligent search solutions.
• Build generative AI workflows using LangChain, LangGraph and LlamaIndex.
• Improve retrieval with chunking, reranking, fusion and grounding strategies.
• Evaluate LLM outputs, identify failure patterns and improve accuracy and reliability.
• Develop structured evaluation approaches to measure AI quality and guide improvements.
• Explore model optimization and instruction tuning where appropriate.
• Engineer scalable Python-based AI services and integrate into platforms.
• Work with AWS cloud infrastructure and take technical ownership to guide architecture.

Skills

Python

AI in prod

RAG orchestration

LangChain

LangGraph

LlamaIndex

Vector search

Model evaluation

Scalable design

AWS

Tools

Databricks

GraphRAG

Job description

What happens when RAG isn't retrieving the right information, agents make the wrong decisions or LLM outputs aren't good enough?

We're looking for the engineer who knows how to investigate those problems, challenge the architecture and build something better.

We're partnering with an established organisation making significant investments in AI, intelligent search and generative technology.

This is an opportunity for a Senior AI Engineer to take a leading hands-on role in developing sophisticated AI solutions, with a particular focus on production engineering, retrieval performance, evaluation and scalable architecture.

The challenges you'll tackle

• Designing and developing production-grade RAG pipelines and intelligent search solutions.
• Building generative AI and agentic workflows using LangChain, LangGraph and LlamaIndex.
• Improving retrieval using advanced chunking, reranking, retrieval fusion and grounding strategies.
• Evaluating LLM outputs, identifying failure patterns and improving accuracy, robustness and reliability.
• Developing structured evaluation approaches to measure AI quality and guide technical improvements.
• Exploring model optimisation, fine-tuning and instruction tuning where appropriate.
• Engineering scalable Python-based AI services and integrating them into wider platforms.
• Working with cloud infrastructure, with a preference for AWS.
• Taking technical ownership of solutions, contributing to architecture and mentoring other engineers.

What we're looking for

• Strong commercial Python engineering experience.
• Proven experience designing, building and deploying AI/ML applications in production environments.
• Excellent understanding of RAG, LLM orchestration, embeddings and vector search.
• Hands-on experience with LangChain, LangGraph or LlamaIndex.
• A strong understanding of model evaluation and experimentation, not just prompt engineering.
• Experience building scalable systems with maintainability, testing and performance in mind.
• Confidence to own technical decisions, challenge approaches and work collaboratively with senior stakeholders.
• Experience with GraphRAG, Databricks or customer-facing AI products would be a bonus.

What's exciting about this opportunity?

You'll be part of a business where AI is a major strategic investment, not a side project.

You’ll have the opportunity to influence architecture, solve genuine engineering challenges, work with experienced technical specialists and help shape the next generation of AI-powered products.

This role will suit someone who is equally comfortable writing production code, designing complex systems and explaining why one technical approach is better than another.

If you've built AI systems that real users depend on, and want to take that experience further, we’d love to hear from you.