Mastercard unveils A2A payments sandbox in the UK

Mastercard is set to offer UK financial institutions access to its fifth-generation account-to-account (A2A) instant payments technology, via a secure sandbox launching later this year.

The sandbox will allow banks and fintechs to experiment with new features and validate next-generation payment services in a trusted, risk-free environment, helping to modernize the UK’s A2A payments infrastructure.

By leveraging Mastercard’s latest A2A switching technologies, participants can test new use cases without disrupting live systems, enabling them to innovate at pace and enhance their service offerings.

The sandbox will support a broad range of payment flows — including person-to-person, person-to-merchant, and business-to-business transactions — across both traditional retail and digital asset use cases. One notable feature is the ‘five-leg credit transfer’ with confirmation of funds, which enables consumers to make a retail payment with instant confirmation of funds for the merchant.

Built on international ISO20022 standards, the sandbox supports rich transaction data that can improve fraud prevention and enable new value-added services. Its design also aligns with the UK government’s National Payments Vision (NPV), which outlines ambitions for a more modern, competitive payments landscape capable of driving economic growth.

With research from EY suggesting a potential £9 billion annual uplift to GDP from modernizing the UK’s A2A payments systems, this initiative offers a significant step toward unlocking that potential. Banks and fintechs will be able to prepare for the future by testing new capabilities and collaborative solutions in a realistic environment — supporting the safe rollout of enhanced payment options to customers and businesses across the UK.

The sandbox is built on Mastercard’s cloud-ready ‘Next Generation A2A Instant Payment’ platform, featuring a developer-friendly interface and robust API access to simplify integration.

Peter Reynolds, executive vice president at 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.

Jana Mackintosh of UK Finance

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

Jana Mackintosh, managing director for payments and innovation at UK Finance, added: “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.”

Further reading: Open Banking ecosystem reacts to UK government’s National Payments Vision