Amazon has acquired Rivr , a Swiss robotics company developing machines for "doorstep delivery," the company confirmed Thursday. Terms of the deal weren't disclosed. Amazon quietly purchased the company earlier this week, but it didn't publicize the acquisition. It announced the deal in a notice sent to third-party delivery contractors. "We want to share that we've recently acquired RIVR, a company focused on technology that can help with doorstep delivery," Amazon wrote in the notice viewed by