23 April, 2025, Amsterdam, The Netherlands – Leading cloud banking platform Mambu announces today that the UK’s fifth largest building society, Leeds Building Society has gone live on Mambu, launching pilot digital savings as the first step in a multi-year core modernisation project.

Having operated on a legacy core system for over 20 years, the move marks a significant step in the strategic digital transformation journey of the building society aimed at modernising its technology stack. The society’s savings product go-live was achieved less than one year after starting the build and is the first step in a comprehensive overhaul that will ultimately extend to its mortgage offering. By using Mambu’s composable architecture and cloud technology, Leeds Building Society is enhancing its ability to meet evolving member demands for a seamless, quick, and effective financial experience.

This milestone coincides with the 150th anniversary of the building society and the United Nations’ ‘Year of the Cooperative,’ a global initiative to promote cooperatives and their contribution to sustainable development. Established in 1875, Leeds Building Society operates as a mutual, meaning it is owned by its one million members across the UK. It has a range of accounts and services which help its members save money and buy a home which is at the heart of its purpose – to put homeownership within reach of more people, generation after generation.

The society’s partnership with Mambu sets a precedent for digital transformation across the broader building society sector showcasing the industry's shift towards next-generation cloud platforms.

"Our partnership with Mambu continues to go from strength to strength. We’ve spent the past year building the engineering foundations for the complete overhaul of our technology and we are delighted to see the technology being used for live savings accounts. These foundations provide the sustainability we need to support our million members and the £30bn of their money we look after, while also giving us the flexibility to continue to help ever more people into home ownership.

Partnering with Mambu provides us with a solution that brings the best composable architecture and cloud technology coupled with innovative functionality that matches the very best in the industry. This strategic move will mean we can spend more time improving the lives of our members and less on worrying about our legacy technology experiences. We’re looking forward to the next steps on our journey together."

Rob Howse

Chief Operating Officer

Leeds Building Society joins a growing roster of 40+ UK financial trailblazers leveraging Mambu’s cloud-native core banking technology, including Allica Bank, Interbridge Mortgages, Chetwood Bank, Recognise Bank, Tandem Bank, and Tide.

Meet Mambu at the BSA Conference

To learn more about how Mambu is enabling building societies to modernise and innovate, visit us at the Building Societies Annual Conference in Birmingham or contact our team.