Mastercard Sandbox Allows Experimentation into the ‘Art of the Possible’ for the UK National Payments Vision

Picture the excitement of experimenting with cutting-edge payment technology, where developers can safely test new features and capabilities without impacting critical infrastructure. Twenty years ago, the UK blazed a trail in developing real-time payments, and today UK banks can reignite that advantage, by accessing Mastercard’s latest account-to-account switching technologies to innovate, test and refine the next generation of payment services, all within a trusted and secure environment. 

Starting later this year, Mastercard will provide access to its fifth generation A2A instant payments technology via a sandbox. Offering an environment for UK banks and financial institutions to experiment, validate and collaborate across new ways to pay and modernize the UK’s A2A payment ecosystem using Mastercard’s innovative payment technology.  

The scope and potential for ideas is considerable with banks and FIs able to test new flows, including retail and digital assets, across person to person, person to merchant, and business to business use cases. 

For example, the sandbox will enable banks and fintechs to implement a “5-leg credit transfer” with confirmation of funds, meaning that a consumer can make a retail real-time payment with the merchant getting instant confirmation of payment. This functionality is a significant step forward in bringing new ways to pay to the UK market and increasing merchant and consumer choice. 

The sandbox will adhere to modern international ISO20022 standards, which provides several new advantages thanks to the rich data provided, including improvements in the amount of data that can flow alongside the transaction. The rich data allows for new ways to significantly enhance fraud detection and reduction, as well as future advancements. 

Toward the end of last year, the UK government published the National Payments Vision (NPV), which outlines its ambition for the payments sector and how to boost economic growth through the adoption of modern services. The A2A sandbox shows how this can be possible, allowing for banks and fintechs to prepare for the next stage in the UK’s payments evolution.  

Modernization of the UK’s A2A infrastructure comes with significant potential benefits. According to an EY report, published in March 2025, noted that there was a potential £9bn uplift to GDP annually. The sandbox is a first step in showing how this growth can be unlocked, providing the proving ground for new infrastructure capabilities and new products.  

As well as the development of new features the sandbox will also offer insight into the future, and what a new account-to-account infrastructure can do for the UK. Built on Mastercard’s Next Generation A2A Instant Payment platform, this cloud-ready solution gives powerful, but simple, front-end tools with a clean user experience and developer portal while the back-end offers powerful functionality with API access to simplify integration.  

Speaking about the possibilities of the sandbox, Peter Reynolds, Executive Vice President, Mastercard Real Time Payments said, “Account-to-account payments in the UK are already an enormous part of the UK’s financial landscape. The Mastercard A2A instant payments Sandbox opens our innovative technology to our partners to develop and test new potential services. Alongside the UK government’s National Payments Vision, we’re setting out a bold vision of the future in A2A real-time payments”.  

Mastercard demonstrated the value of the sandbox on stage at UK Finance’s Digital Innovation Summit on June 24, with a specific focus on how A2A can help accelerate retail payments.  

Jana Mackintosh, UK Finance Managing Director for Payments and Innovation said, “It’s always exciting to see innovation coming to the market. Mastercard’s sandbox demonstration at our Digital Innovation Summit is a great example of how we can bring the National Payments Vision to life. I hope we’ll see many more industry-led solutions that help drive progress across our payments landscape.”