Amazon has acquired Rivr, a startup specializing in stair-climbing delivery robots, as the e-commerce giant continues to explore automated delivery solutions.

Rivr develops robotic systems designed to navigate stairs and deliver packages directly to customers' doorsteps. The acquisition represents Amazon's ongoing efforts to enhance its last-mile delivery capabilities through automation technology.

Amazon and founder Jeff Bezos had previously invested in the startup before completing the full acquisition. The prior investment relationship suggests Amazon had been monitoring Rivr's technology development for potential integration into its delivery operations.

The deal signals Amazon's broader interest in doorstep delivery solutions that could reduce reliance on human delivery drivers for certain types of deliveries. Stair-climbing robots could potentially serve customers in multi-story buildings and other locations where traditional wheeled delivery vehicles face obstacles.

Financial terms of the acquisition were not disclosed. Amazon has not announced specific timelines for testing or deploying Rivr's robot technology in its delivery network.