Walmart is expanding its advertising partner program to help ramp up even more spending on a platform that has seen a tenfold increase in businesses buying ads in the past year, according to Lex Josephs, VP of ad sales and ad tech partnerships at Walmart Connect.

On Tuesday, Walmart announced the addition of new advertising technology partners, Stackline, Tinuiti and Harvest Group, which are now able to pipe into Walmart Connect, the online ad platform run by the retail giant. By adding these three partners, Walmart nearly doubled the number of ad tech firms in the still-young program.

The expansion comes as Walmart says it is seeing a surge in advertiser interest. The number of sponsored search ads—the paid results that appear when people shop on Walmart.com—rose 185% in 2020 over 2019, Walmart said on Tuesday. The number of advertisers on Walmart.com, buying through the partner program, also rose by a factor of 10 in 2020, Walmart said.

The advertising interest was related to the spike in consumers shopping online during the COVID-19 pandemic, which made e-commerce sites essential destinations for brands to reach customers. “We candidly need more partners to help scale our business for the three customer advertising segments that we work with,” say Josephs, in a recent phone interview, “which are enterprise advertisers, so think of your big CPG companies like a P&G or a Kellogg’s or a General Mills; and then our mid-market advertisers, so think of someone like a Sargento Cheese or SharkNinja; and then our emerging [first-party and third-party] sellers.”

Walmart Advertising Partner Program is similar to programs run by Amazon, Facebook and Google, and other major internet companies that develop self-serve, automated ad tools. The advertising partners typically work with hundreds and thousands of brands, and they develop special technology that gives the advertisers sophisticated ways to buy internet ad inventory, especially using data and information for better targeting.

Walmart is still fairly new to the internet advertising space, and only launched the advertising partner program last year with a handful of technology companies—Flywheel, Pacvue, Kenshoo and Teikametrics. The advertising partners tap into what’s known as an API, or application programming interface, and through that platform they help brands run ad campaigns. Walmart’s API is set up to power search advertising, the kind that returns sponsored product results to people shopping on its site.

“More and more of our advertisers want transparency,” Josephs says. “They want control and they really want access to a self-serve sponsored product interface that also allows for performance-reporting dashboards in near real-time.”

Walmart is among a growing core of classic retailers starting to see the value in building media platforms, where they run popular websites and have unique data on their customers that helps brands fine-tune campaigns. Walmart.com sees more than 150 million visitors a week, and brands on the site need ways to appear on its digital shelves. In recent years, Target, Kroger, CVS and others have developed digital ad platforms. The most successful, so far, however, has been Amazon, which generated $21.5 billion in revenue in 2020 under the segment of its business that includes advertising. That was up from $14 billion in 2019.

Walmart has been making improvements to its ad business by building technology like the advertiser partner program. This year, Walmart renamed the ad platform Walmart Connect.

Walmart also is developing the display side of the advertising business, which is the portion of ads that focuses more on larger brand campaigns and video ads. Walmart can use its substantial consumer data to power ads that reach beyond Walmart.com, similar to how Amazon and Google reach publishers outside their own properties.

In January, Walmart picked The Trade Desk as technology partner for its display advertising business.

“We’re just seeing this incredible shift of national media dollars becoming more into retail media, and there’s this blurring of, well, is Amazon retail or is it a massive national media platform? Is Walmart retail media or is it in fact national media?” Josephs says. “So, because we have tremendous reach of 150 million customers, coupled with omnichannel data—as well as the ability to then know how the customer is shopping in-store and online—it creates this very powerful formula. So we’re definitely seeing a shift of national media dollars into us, and we’re this hybrid of retail and national presence because of our scale.”