Senior AI Engineer

Octopus Energy Group; City Of London; On-site; GBP 100,000 - 125,000; Full time

Job summary

A leading energy technology company in London is seeking a Senior AI Engineer to own and scale systems for generative AI models. This role involves building AI platform services, developing knowledge bases, and creating evaluation frameworks. Candidates should have experience in AI application development and a strong understanding of AI evaluation metrics. The environment is fast-paced and values autonomy, with a strong focus on innovation and moving towards a low-carbon future.

Benefits

Flexible salary discussions

Unique company culture

Employee benefits and perks hub

Qualifications

• 2+ years of experience of working with LLMs.
• 5+ years of experience building Python‑based applications.
• Experience of different ways of evaluating AI models.

Responsibilities

• Build reusable, scalable services that expose GenAI models.
• Maintain knowledge retrieval systems including embedding generation.
• Set up frameworks for monitoring and evaluating AI output quality.

Skills

Deep Understanding of GenAI

Data Product Development

GenAI Application Development

AI model evaluation and observability

Context Engineering and Knowledge Grounding

Software Development Practices

Ability to thrive in a fast moving environment

Tools

Python

Git

CI/CD frameworks

Graph databases

Vector databases

Javascript

Job description

Octopus was founded with a mission to use technology to accelerate us towards a low‑carbon future. That’s why we created Kraken – our own technology platform from scratch which now serves over 70 million households and is a core reason why Octopus is the number one energy supplier in the UK. We do it by hiring clever, curious, and self‑driven people, enabling them with modern tools and infrastructure and giving them lots of autonomy.

We have been using GenAI in live, customer‑facing environments since 2022, including one system that creates tens of thousands of high‑quality emails for our Energy Specialists, combining our deep knowledge of the energy industry and the Octo communication style with customer‑specific data from Kraken.

We are now looking for a Senior AI Engineer. You will take ownership of building and scaling the systems that allow Octopus teams to use Generative AI models (LLMs, RAG, agents). This may take the form of a platform, shared services, or other scalable infrastructure. You will work with a cross‑functional team to build out flagship AI projects and will continue to develop the best practice for how we work with AI at Octopus.

You’ll report into the Head of AI and work on developing solutions that genuinely move us closer to Net Zero in a company passionate about building great technology to change the way customers use energy. You’ll have wide open problems to solve, so you’ll need to be comfortable with ambiguity, figuring out an approach and validating it fast.

What You’ll Do

• Design and Develop AI Platform Services – Build reusable, scalable services that expose GenAI models, knowledge retrieval pipelines, and agent workflows to application teams.
• Knowledge Base Development – Build and maintain knowledge retrieval systems including embedding generation, chunking, and strategies for database management.
• AI Ops, evals and observability – Setting up frameworks for monitoring and evaluating AI output quality (relevance, accuracy, safety, drift, cost) and platform observability (latency, cost, usage).
• Centre of Excellence – Act as a centre of excellence for the whole business in the technical side of AI and LLMs usage, setting best practices and accelerating adoption.
• Context Engineering – Design systems for prompt assembly: Create prompt templates, system prompts and guidelines for platform users.
• Governance and Guardrails – Create governance layers for implementing PII redaction, prompt filtering etc.

What You’ll Have

• Deep Understanding of GenAI – 2+ year experience of working with LLMs and using techniques such as tool calling, agentic workflows, finetuning and reinforcement learning.
• Data Product Development – 5+ years of experience building Python‑based applications and/or data products, with hands‑on work in data‑intensive and machine learning systems.
• GenAI Application Development – Hands‑on experience of building AI applications which have been successfully deployed into production.
• AI model evaluation and observability – Experience of different ways of evaluating AI models and applications. Implementing logging, tracing, and monitoring in systems.
• Context Engineering and Knowledge Grounding – Experience of optimising and grounding GenAI models and applications through prompt design, RAG and knowledge base integration.
• Software Development Practices – Strong grounding in Git, testing, CI/CD frameworks.
• Ability to thrive in a fast moving environment – Dealing with ambiguity, setting clear priorities, and translating ideas into actionable plans.

It would be great if you had

• Backend Development – Experience designing and building applications and services that encapsulate business logic, data and information flows and connect AI models into wider applications.
• Pipeline Design and Build – Experience integrating different types of databases and building and optimising data pipelines.
• Vector Databases and Knowledge Graphs – Familiarity with graph and vector databases such as Pinecone and Neo4J.
• Javascript – Familiarity with Javascript, particularly within backend build.

💚 Why else you’ll love it here

• 💰 Wondering what the salary for this role is? Just ask us! On a call with one of our recruiters it’s something we always cover as we genuinely want to match your experience with the correct salary. The reason why we don’t advertise is because we honestly have a degree of flexibility and would never want salary to be a reason why someone doesn’t apply to Octopus – what’s more important to us is finding the right octofit!
• 🎉 Octopus Energy Group is a unique culture. An organisation where people learn, decide, and build quicker. Where people work with autonomy, alongside a wide range of amazing co‑owners, on projects that break new ground. We want your hard work to be rewarded with perks you actually care about! We won best company to work for in 2022, on Glassdoor we were voted 50 best places to work in 2022 and our Group CEO, Greg has recorded a podcast about our culture and how we empower our people. We’ve also been placed in the top 10 companies for senior leadership.
• 🎁 Visit our UK perks hub – Octopus Employee Benefits

If this sounds like you then we’d love to hear from you.

Are you ready for a career with us? We want to ensure you have all the tools and environment you need to unleash your potential. Need any specific accommodations? Whether you require specific accommodations or have a unique preference, let us know, and we’ll do what we can to customise your interview process for comfort and maximum magic!

Studies have shown that some groups of people, like women, are less likely to apply to a role unless they meet 100% of the job requirements. Whoever you are, if you like one of our jobs, we encourage you to apply as you might just be the candidate we hire. Across Octopus, we’re looking for genuinely decent people who are honest and empathetic. Our people are our strongest asset and the unique skills and perspectives people bring to the team are the driving force of our success. As an equal opportunity employer, we do not discriminate on the basis of any protected attribute. Our commitment is to provide equal opportunities, an inclusive work environment, and fairness for everyone.