Walmart built a giant vending machine that retrieves groceries

Walmart is trying to make it easier to pick up online grocery orders.

The retailer is testing a giant self-service kiosk in the parking lot of a supercenter in Warr Acres, Oklahoma, where customers can pick up online grocery orders without interacting with any employees.

Here's how it works: customers purchase and pay for groceries online, then Walmart employees pick and pack their orders and store them in bins in the 20-foot-by-80-foot kiosk.

The kiosk has refrigerators and freezers inside that keep the groceries fresh.

When customers arrive to pick up their orders, they walk up to the kiosk and type in a code and their groceries appear in 60 seconds or less.

There is no cost for picking up groceries, but customers must spend at least $30 per order to use the service.

The kiosk is open 24 hours a day, 7 days a week, and it's able to fulfill hundreds of customer orders in a single day, according to Walmart spokesman Scott Markley.

More than 30,000 grocery items, including fresh produce, meats, and dairy products, are available for online ordering and pickup.

"Especially for busy families with kids, grocery shopping used to take a couple of hours on the weekend," Markley said. "You can now pickup your groceries in just a few minutes and have more time back in your day."

Walmart is testing a similar, though smaller, structure in some of its stores for picking up non-grocery online orders.

The pickup kiosks are part of a broader effort by Walmart to more seamlessly integrate its online and offline services, and leverage the power of its vast network of stores to better compete with Amazon.

Another recent example of this is effort is Walmart's new discount for customers who ship purchases to one of its stores instead of to a home or elsewhere. The discount gives customers as much as $50 off purchases of large items like televisions.