Facebook Inc. says it is testing a payments product that would let online shoppers make purchases in mobile apps using their Facebook login data.

The tool aims to speed up consumers’ purchases because shoppers would not have to type their credit or debit card information. However, only consumers who have their credit card information on file with the social network can use the product. The social network declines to disclose how many of its 1.15 billion monthly active users have their credit card information on file with Facebook.

When a shopper uses his Facebook login to pay, the retailer can access the consumer’s credit card information. The merchant then uses its payments processor to complete the transaction.

“The test makes it easier and faster for people to make a purchase in a mobile app by simply pre-populating your payment information,” Facebook spokeswoman says.

The spokeswoman says that the test is limited to “one to two partners.” One of those partners is flash-sale apparel e-retailer JackThreads, which is No. 319 in Internet Retailer’s 2013 Top 500 Guide.

JackThreads is a logical partner for Facebook because 50% of total sales stem from mobile devices, with 89% of mobile sales coming from smartphones and 11% from tablets. 90% of those sales come through the retailer’s iPhone, iPad and Android apps. The other 10% comes through its smartphone m-commerce site and its e-commerce site for tablets.