According to Business Insider, the retailer is expanding its “Scan & Go” service, which allows customers to scan the barcode of certain items and pay for them directly through a dedicated mobile app. Users must simply show their digital receipt to a Walmart employee, and then can leave the store without waiting to pay a cashier.

While Walmart initially tested the “Scan & Go” technology in 2014, the service had only been rolled out in 25 stores. It will now be made available in 100 new stores across 33 states, reports Business Insider. To find out if there is a participating store nearby, customers can open the app and find a list of those where “Scan & Go” is available.

Read: Walmart Is Putting Shelf-Scanning Robots in Over 50 U.S. Stores

Walmart isn’t the only retailer to offer services that allow for mobile checkout. Kroger recently expanded its “Scan, Bag, Go” service to 400 more stores, and Sam’s Club already offers a similar technology in its locations nationwide. Even Amazon is piloting a brick and mortar store without checkout lines, called Amazon Go.

To set itself apart, Walmart is also in the process of developing a cashierless store. Business Insider reports that the concept is being tested by Walmart’s incubator, Store No. 8, and uses computer vision “to track and charge purchases,” which could allow customers to avoid scanning items or showing their receipts entirely.