Design, build, test and deploy machine learning and generative AI models for production; prepare and refine datasets; integrate AI services with applications and cloud; document models, pipelines and APIs; monitor, evaluate and improve model performance; collaborate with engineers, data specialists and business teams.
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.
- 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.
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
Inclusivity
At Pay.UK, we value diversity and inclusivity. Research has shown that candidates from underrepresented groups may hesitate to apply unless they meet all the requirements listed. We encourage all qualified candidates to apply, regardless of how closely their skills and experience match the requirements. We are committed to supporting accessibility needs and creating a welcoming environment for all employees. Become part of our team and contribute to the creation of an inclusive work environment that values everyone's unique input.
Who we arePay.UK is the recognised operator and standards body for the UK's interbank retail payment systems. We provide the infrastructure and services that millions of people and businesses rely on every day, including Bacs, Faster Payments and the Image Clearing System for cheques, the Current Account Switch Service and Confirmation of Payee. Together, these services help keep money moving safely, securely and reliably across the UK and play an important role in supporting the economy.
In 2025, the UK's retail payment systems processed more than 12.5 billion transactions worth over £11 trillion. Since its launch in 2013, the Current Account Switch Service has successfully helped consumers and businesses switch more than 12 million current accounts. These services help people receive their salaries, pay their bills, make payments and manage their finances with confidence.
Our purpose is to provide the trusted infrastructure, standards and services that underpin UK retail payments. We deliver safe, resilient and efficient payment systems while working collaboratively with industry, regulators and stakeholders to strengthen resilience, tackle fraud, improve access and support innovation across the payments landscape. As the ecosystem evolves, we are continuing to develop our capabilities in areas such as data and AI, enhancing operational insight and helping to build a modern, trusted payments ecosystem.
Learn more about life at Pay.UK by hearing what employees have to say, click here to view videos.
Benefits & additional information- 12% Non-contributory pension
- Discretionary annual bonus
- 30 days annual leave (excluding bank holidays)
- Private medical insurance, life assurance, income protection, health cash plan, dental insurance, Bupa medicals etc
- Employee assistance programme
- Cycle to Work Scheme
- Season ticket loan
- Annual fitness subsidy of up to £500 per annum
- Working from home policy - minimum 40% in the office (eg. 2 days in the office over a 5 day working week)
Please note:
- Some of our benefits are only available to colleagues after meeting the requirements of the probationary period
- Pay.UK employee benefits are not available to contractors and are only available to permanent and fixed-term employees
Pay.UK London, England Office
London, United Kingdom
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