Members found deals on Prime Day organized by more than 20 of the most-shopped-for themes — from pet lovers to gardeners. The most popular themes on Prime Day were home chefs, techies and for the home, the company said.
"To those customers who tried Prime for the first time and our long time members, thank you for a great Prime Day," Greg Greeley, the Amazon Prime division's vice president, said in a statement.
"Our teams around the world will keep working to add more and more to your membership, so Prime continues to make your life better every day. We are already looking forward to our Prime Day celebration next year."
The first Prime Day was held on July 15, 2015, as a way to mark the company's 20th anniversary, and it proved to be such a success in boosting sales and bringing in new Prime members that the company did it all again on July 12, 2016.
This year, Amazon declared July 11 to be Prime Day, but the savings kicked off even earlier for Prime members and were extended to last for 30 hours, up from the typical 24. Amazon.com was offering new deals as often as every five minutes, the company said, reaching 13 countries and making the day more of a global phenomenon.
"Never is there a better day to illustrate just how far ahead Amazon is compared to other retailers," Radial's Stefan Weitz, the commerce technology firm's senior vice president of technology, told CNBC. "This is highlighting a massive differentiation between Amazon and everyone else."
Amazon's pricing pressure and customer experience pressure were king to other retailers on Prime Day, Weitz said. He added that seven major brands represented by Radial, which are sold on Amazon.com, saw "significant sales" as a result of the 30-hour shopping surge.
Some of the best Prime Day discounts across the board included those on Amazon's own electronic devices, such as the Echo and the Kindle. There were also significant discounts on some of Amazon's private-label grocery and apparel products.
With an Amazon-Whole Foods deal in the works, more online shoppers were seen browsing Amazon.com for supermarket staples and everyday essentials, which notably haven't been best-sellers for the internet giant in past Prime Days.
"It's no secret that some of Prime Day's best deals have been on Amazon products — Audible, Kindle or even Prime memberships," Maya Mikhailov, co-founder of GPShopper, told CNBC.
Yet considering how this year Amazon was using Prime Day to introduce customers to the company's newest grocery offerings, and with tens of millions of Prime members, traditional grocery retailers should be "very worried," Mikhailov said.
Early signs hinted that Amazon's annual shopping event would grow in 2017. In a nationwide survey of 1,200 U.S. consumers by Market Track, 58 percent said they would shop Prime Day deals, up from the 34 percent who said they would participate last year.
"Aside from a minor glitch in the first hour, Amazon had very fast load times despite the heavy traffic of Prime Day," said Mehdi Daoudi, CEO of Catchpoint, a digital experience intelligence company. "This is especially notable because their sites were heavy with many product images, and still they loaded faster than the competition."