Walmart is adding four new fulfillment centers to its existing capacity, a move that will bring more than 4,000 jobs and make next- or two-day shipping available to more Americans.

The announcement comes at a time when consumers are relying on packages being shipped to their homes more than ever before. While online ordering has continued to increase over the years, the pandemic saw a huge surge in such orders as Americans stayed home during lockdowns and had essential items and other goods delivered to their doors. While coronavirus restrictions have eased, many consumers’ online ordering habits remain.

Aside from a growth in online orders, Walmart and other retailers are trying to make sure that their shipping speed keeps pace with rival Amazon, which offers same-day, one-day and two-day delivery options for those who pay for its Prime membership.

Walmart said Friday that its four next generation fulfillment centers will be built over the next three years. The centers, which feature robotics and machine learning, double the capacity and number of orders allowed to be fulfilled in a day. The four fulfillment centers will be able to provide 75% of the U.S. population with next- or two-day shipping on millions of items, including Marketplace items shipped by Walmart fulfillment services.

When combined with its traditional fulfillment centers, Walmart said it can reach 95% of the U.S. population with next- or two-day shipping. The company can offer same-day delivery to 80% of the U.S. population when using the inventory and capabilities available at its stores.

The first next generation fulfillment center will open over the summer in Joliet, Illinois, 45 miles (72.4 kilometers) southeast of Chicago. Another one will open next spring in McCordsville, Indiana, 20 miles (32.2 kilometers) northeast of Indianapolis. A third one will open in Lancaster, Texas in the fall of 2023, and the fourth one is set to open in 2024 in Greencastle, Pennsylvania. They join the pilot next-generation fulfillment center already operating in Pedericktown, New Jersey.

Walmart currently has 31 dedicated eCommerce fulfillment centers, 4,700 stores and 210 distribution centers.