Amazon wants other online retail sites to add its "login and pay" feature, further tying merchants to its payments system.

The company introduced the new integration Tuesday, saying it "streamlines" a merchant's payment process and boosts other sites' customer base with its own. Amazon said earlier this year that it has more than 215 million active customer accounts, all of which log in to pay on Amazon's site.

"Login and Pay with Amazon enables companies to make millions of our customers their customers by inviting online shoppers with Amazon credentials to access their account information safely and securely with a single login," Tom Taylor, vice president of Amazon Payments, said in a press release.

When Amazon extended the log-in to other companies it owns, it saw an increase of customers to those sites. According to Amazon, 40 percent of Zappos's new customers choose to sign in to Zappos.com with an Amazon account. During the month of May, when the log-in was first integrated, Woot customers picked Amazon's log-in twice as much as other social log-ins, an Amazon spokeswoman said.

Additionally, Amazon is testing the feature with in-flight Internet provider Gogo, and Gogo's customers are "highly satisfied" with the service, according to the release.

 

Other retail sites already use the company's Amazon Payments system to let customers pay with Amazon at checkout. The log-in feature adds another layer, allowing merchants to use Amazon's stored customer information to provide other services like tracking orders, purchase history, and discounts. The company stressed that it is not sharing any credit card information with other merchants as part of the process.