McDonald’s is rolling out an electronic loyalty program in about 570 US locations as it seeks to attract younger customers.

According to Bloomberg, the mobile solutions marketer Front Flip has introduced a loyalty application in 420 McDonald’s stores that rewards customers with free food and other offerings.  It is adding another 150 locations to the scheme over the next month.

Under the program, customers can win prizes such as free cheeseburgers and buy-one, get-one-free Big Macs after scanning a QR code, a pixelated square that can be read by a smartphone.