Add Walmart to the growing list of companies rolling out mobile payment services in 2015. The retail giant Thursday introduced its own service to rival Android Pay and Apple Pay -- dubbing it Walmart Pay.

While it bears a name similar to the mobile payment systems from Google and Apple, Walmart’s service doesn’t use the near-field communication (NFC) wireless technology found in the other two mobile wallets. Instead, Walmart Pay has customers launch the Walmart app and scan a QR code using a smartphone camera to facilitate the transaction.

It works on both iOS and Android, as well as with major credit, debit and Walmart cards. But it only works in the retail stores. Initially, Walmart Pay will roll out to stores this month. A nationwide launch is expected to be completed in the first half of next year.

What’s missing from the picture is CurrentC, a yet-to-launch mobile payment service backed by Merchant Customer Exchange -- a consortium of merchants such as Walmart, CVS, Sears, Gap and Hobby Lobby. But Walmart hinted it may be able to support additional mobile wallets at a later date.

“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," Daniel Eckert, Walmart senior vice president of services, said in a press statement. “The result is an innovation that will make the ease of mobile payments a reality for millions of Americans.”

While CurrentC was relatively unknown in the mobile payments space initially, it was thrust into the spotlight in 2014 when its partner merchants CVS and Rite Aid disabled the contactless payment features of in-store terminals following the launch of Apple Pay. Rite Aid reversed course and started accepting Apple Pay at its stores last August.

Mobile payments are just starting to get a foothold in the U.S., but in 2016, in-store mobile transactions are expected to triple to $27.05 billion, up from an estimated $8.71 billion this year, eMarketer predicted.