US retail giant Walmart has announced it is launching Walmart Pay, a mobile payments solution for both iOS and Android, in selected US stores, making it the first US retailer to offer its own exclusive mobile payment system.

The system will be introduced on Thursday, and will expand to additional locations in the new year, with the solution expected to be available nationwide by the end of H1 2016. The system is free, allows payments from any major credit, debit or pre-paid card, along with Walmart gift cards, and will be integrated into the brands existing app.

“The Walmart app was built to make shopping faster and easier,” said Neil Ashe, president and CEO of Walmart Global eCommerce. “Walmart Pay is the latest example – and a powerful addition – of how we are transforming the shopping experience by seamlessly connecting online, mobile and stores for the 140m customers who shop with us weekly.”

Walmarts current app is already used by 22m customers a month, and ranks among the top three retail apps on both the iTunes and Google Play stores, giving the mobile payment solution a massive existing audience to tap into.

“The simplicity of ease of Walmart Pay comes not only from how it works, but also in how its been built,” said Daniel Eckert, senior vice president of services at Walmart US. “We made a strategic decision to design Walmart Pay to work with almost any smartphone and accept almost any payment type – even allowing for the integration of other mobile wallets in the future. The result is an innovation that will make the ease of mobile payments a reality for millions of Americans.”

While the initial announcement did not address any international expansion plans, with Walmart owning the Asda supermarket chain in the UK, rival brands are no doubt eyeing this development with great interest, given the high adoption rate of mCommerce in the UK.