6 River Systems Inc., a Waltham, Mass.-based warehouse automation startup best known for its Chuck autonomous mobile robot (AMR), was acquired by Shopify for $450 million. Shopify Inc., the Canadian e-commerce giant, paid 60% in cash and 40% in shares for the deal, which is slated to close in Q4 2019.

In June, Shopify launched its Fulfillment Network service, which it said it hopes will speed up delivery times and lower shipping costs for its customers. Shopify’s fulfillment centers, which are located throughout the U.S., support merchants that ship between 10 and 10,000 packages per day. Shopify plans to eventually support 3 to 30,000 packages per day.

The acquisition, Shopify said, “is a critical step to accelerate its growth.” 6 River Systems’ fulfillment software and robotics technology will help increase the speed and efficiency of the warehouses in the Fulfillment Network.

“Shopify is taking on fulfillment the same way we’ve approached other commerce challenges, by bringing together the best technology to help everyone compete,” said Shopify CEO Tobi Lütke. “With 6 River Systems, we will bring technology and operational efficiencies to companies of all sizes around the world.”

There are a lot of players in the warehouse robotics space, but 6 River Systems was founded by some of the best — Jerome Dubois, Rylan Hamilton, and Chris Cacioppo. Dubois and Hamilton met while working as executives at Kiva Systems, which was acquired by Amazon in 2012 for $775 million. Cacioppo was formerly director of R&D at education hardware company Mimio.

“By joining Shopify, we’re changing the game of fulfillment,” said Dubois. “Together, we will help thousands of businesses improve their fulfillment operations, with an easy-to-learn solution that can more than double productivity and improve accuracy.”

Prior to the acquisition, 6 River Systems raised about $46 million in venture capital. It closed a $25 million Series B in spring of 2018, in addition to a $15 million Series A coming in July 2017 and a $6 million seed round in March 2016.

6 Rivers Systems said it will continue to sell its solutions to other warehouses, not just Shopify’s. This is a different approach than Amazon took with the Kiva robots, which are used exclusively by Amazon. Shopify said its expects 6 River Systems to generate annual revenue of $30 million in 2020.

The Chuck AMR uses machine learning and artificial intelligence to help human workers minimize walking, and it integrates with leading warehouse management systems. The company also offers Mobile Sort smart kiosks, which debuted at ProMat 2019. Its customers include DHL, Lockheed Martin, Office Depot, and XPO Logistics.

6 River last week announced a mobile picking partnership with Soft Robotics, a Bedford, Mass.-based developer of soft grippers.