When Amazon makes a big push to deliver your order faster, the competition has to react. That's exactly what Walmart just did by offering its own version of one-day shipping, albeit on a much smaller scale.

Walmart is this week introducing NextDay delivery "on a wide range of general merchandise" offered through Walmart.com. The company is also keen to point out this offer does not require a paid membership as is required for Amazon Prime.

NextDay delivery will be slowly introduced across the US, with Phoenix and Las Vegas getting it first before Southern California customers are added "in the coming days." The aim is to have 75 percent of the US population covered by the end of 2019, which will include 40 of the top 50 US metro areas.

There are a few caveats to keep in mind about this fast delivery offer. The number of products that qualify for NextDay is limited to around 220,000 items, but Walmart states they are the most frequently purchased items. You also need to spend at least $35 in order to qualify for the service, and there will be a cut off time each day as you'd expect.

Walmart claims NextDay deliveries actually cost the company less to fulfill. That's because qualifying items will be made available at the fulfillment center closest to each customer being offered the service. By doing that, Walmart deliveries travel the shortest distance and will typically only require one box for transport. I can see the logic in that as long as all products ordered really are available from a single location close to the customer.

Amazon set itself a more lofty goal last month when it announced free two-day shipping is set to become free one-day shipping for Prime members. Achieving that requires spending $800 million this year on building infrastructure, plus offering existing employees a big incentive to quit and start delivering packages instead.

If we ever need reminding why competition is good, this is a great example. As consumers our deliveries are getting faster as two giants of the online retail world compete for our dollars.

This article originally appeared on PCMag.com.