Amazon is a devilishly simple everything-store. You buy it. It shows up. Fast. But, at the bottom of its complicated machinery is a nearly invisible workforce tasked with getting those orders to your doorstep. It’s a network of supposedly self-employed, utterly expendable couriers enrolled in an app-based program which some believe may violate labor laws. It’s Amazon Flex, and it makes Amazon’s “last-mile” deliveries—the final trip from a local facility to the customer.