Google and Walmart are joining forces to take on Amazon (AMZN, GOOG, WMT)

Starting in September, Google's commerce platform, Google Express, will count America's largest retailer among its list of vendors, the company announced Wednesday.

Customers will be able to place orders with Walmart at Express.google.com, on the Google Express app, or through Google Assistant-enabled devices like Google Home.

Walmart will be the largest vendor on the platform when it joins.

The coming integration with Walmart is expected to go deeper than that with any current Express retailer — Google's head of commerce, Sridhar Ramaswamy, called the partnership "the first of its kind."

Ramaswamy said customers could link their Walmart and Google accounts, allowing integrated features like a shortcut to reorder items frequently bought from Walmart through the Google Assistant voice software.

Telling a Google Assistant to "add paper towels" to your cart, for instance, would add your most frequently purchased size and brand of paper towels. Walmart also plans to allow customers to pick up purchases in-store for a discount.

The partnership puts Walmart further in competition with Amazon, which has a similar service in Alexa. Alexa integrates voice-control and speech-recognition technology to enable customers to place orders via voice using the retailer's Prime service.

Google is also removing the $95-a-year membership fee for Google Express, which previously enabled customers to get free two-day shipping at retailers. Now each store on the platform will have its own threshold for free shipping. Walmart's policy will mirror its website, with orders of at least $35 receiving free two-day shipping.

Speaking with Business Insider, Walmart's e-commerce CEO, Marc Lore, was optimistic about the future of shopping using voice.

There will be "certain specific use cases in shopping where voice will be the preferred means," Lore said. "You can imagine you're driving home from work and ordering from groceries via voice and picking them up at your local Walmart on the way home."