Amazon Go faces unlikely challenge from checkout-free startup

Amazon.com Inc. employees shop at the Amazon Go store in Seattle, Washington, U.S., on Wednesday, Jan. 17, 2018. After more than a year of testing with an employee-only focus group, Amazon Go opens to the public Monday in downtown Seattle, putting to the test the online retailer's technology that lets shoppers grab what they want and leave without paying a cashier. Photographer: Mike Kane/Bloomberg

Grocers, alarmed at Amazon.com Inc’s rapid growth in Europe, are considering fighting back with the help of a tiny Portuguese startup. 

Sensei, a 16-month-old technology company based in Lisbon that’s backed by Germany’s Metro AG and Portugal’s Sonae SGPS SA, is pitching its technology to European supermarkets as they race the e-commerce giant to open the region’s first checkout-less stores.