Apple rattled tech rivals like Google last year when it entered brick-and-mortar retail with Apple Pay, which lets people use their iPhone to pay for goods in stores. Now Google, which has long offered a similar product for Android phones that hasn’t become widely used, and Square, which helps small businesses accept credit card payments, are searching for new ways to insert themselves into the retail value chain.

Google last fall began testing a service called “Plaso” that allows people carrying Android phones to pay at retailers like Papa John’s and Panera Bread by saying their initials to employees at the cash register, according to four people who have been involved in or briefed about it.