AI Engineer, London, Permanent

We’re looking for an AI Engineer to help us apply AI in a setting where reliability, clarity and trust matter every day. At Pay.UK, you’ll work in an organisation that supports UK retail payments at national scale, with systems processing over 10 billion transactions worth over £11 trillion annually. This is a chance to build practical AI solutions in a complex, highly important environment, while working with colleagues across technology and the wider business.

You’ll join a team that values quality engineering, clear communication and continuous learning. We are transparent, collaborative and open to ideas, and we want someone who can turn AI concepts into well-designed, usable tools and services.

Accountabilities

• Design and build AI solutions that address defined business and operational needs within Pay.UK.
• Develop, test and deploy machine learning and generative AI models for internal tools, workflows or decision support.
• Prepare and refine datasets for model training, evaluation and ongoing performance monitoring.
• Integrate AI services into existing platforms, applications and engineering workflows.
• Create technical documentation for models, data pipelines, APIs and deployment processes.
• Evaluate model outputs, identify risks or limitations, and improve performance through structured testing.
• Collaborate with engineers, data specialists and business teams to translate requirements into working AI applications.
• Monitor live AI solutions, troubleshoot issues and implement updates to maintain reliability and accuracy.

Qualifications, Skills and Experience

• Experience designing, building and deploying AI or machine learning solutions for live production use.
• Experience using Python and AI or machine learning libraries to develop, test and maintain AI solutions.
• Experience preparing datasets, training models and evaluating model performance using structured testing and evaluation methods.
• Experience integrating AI solutions with business applications, APIs or cloud-based services.
• Experience producing technical documentation and explaining implementation choices to both technical and non-technical colleagues.
• Delivery experience with Microsoft copilot Studio is a must. Microsoft Foundry is good to have and/or other LLM technologies.

Pay.UK Behaviours

At Pay.UK, our behaviours are central to who we are and how we operate. They bring our values to life, shape our culture, and guide how we make decisions, collaborate, and respond to challenges across the payments ecosystem. All interview processes will assess the following behaviours:

• Listen to Find Win-Wins - Empathy, Listening and Understanding
• Influence with Courage - Influence, Courage
• Go Horizontal First - Cross Boundary Collaboration
• Take Ownership - Self Development
• Opportunity Mindset - Initiative
• Simplify - Achievement Orientation
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