SAN FRANCISCO — The Windy City is getting the next Amazon Go checkout-free store, the first to open outside of Seattle. The new cashierless store opens Monday in Chicago.

The store uses proprietary technology made up of hundreds of cameras and sensors to see what customers have taken. The Just Walk Out tech allows customers to swipe in with their Amazon Go app, pick up what they want and walk out. When they leave, the items are automatically charged to the credit card on the account, without the need to talk to a cashier or swipe a bar code.

This high-tech solution for a long-standing complaint among shoppers — long checkout lines — has the prospect of shaking up the grocery business. But Amazon is starting small.

The Amazon Go stores are about the size of smallish convenience stores, about 2,000 square feet vs. the average U.S. supermarket, which is around 45,000 square feet.

The stores stock a high-end assortment of grab-and-go lunch foods, as well as chilled beverages, sweets, snacks, ready-made salads and sandwiches, frozen foods, meal kits for dinners, as well as some groceries and sundries.

The original Amazon Go store is located in the first floor of Amazon headquarters. It opened to staff in 2016 and to the public in 2018. Two more have since been launched in Seattle.

The three Seattle stores are popular with Amazon employees and others looking to grab and go quickly.

Amazon said in May it planned to build more Amazon Go stores, naming San Francisco and Chicago as locations.

Amazon is not the only company in the cashierless space. Earlier this month a start-up called Standard Cognition opened the Standard Market in downtown San Francisco. It, too, uses a proprietary app and cameras to track buyers. The store has only limited opening hours and inventory, as it sorts out both the technology and San Francisco’s onerous permitting process.