Amazon is assembling an army of robots. The online retailer announced that it had acquired Kiva Systems - a company that designs robotics aimed at increasing supply chain optimization - for approximately $775 million.

“Amazon has long used automation in its fulfillment centers, and Kiva’s technology is another way to improve productivity by bringing the production directly to employees to pick, pack and stow,” Amazon’s vice president of global customer fulfillment Dave Clark said in a release.

Among Kiva’s customers are internet retailers Zappos.com and Diapers.com, two companies that were recently acquired by Amazon.

Amazon’s acquisition of these retailers and Kiva suggests the company is placing a greater emphasis on delivering a wider range of products to customers faster. Amazon spent $4.6 billion last year on warehouses-the company’s largest operating expense.

Kiva’s Mobile-robotic Warehouse Automation System uses small orange robots to automate a warehouse’s shelving, delivery and inventory operations in order to increase efficiency, Inc.wire reported.