Boxed Wholesale, the fast-growing e-retailer that sells household and business staples in bulk, is rolling out a real-time auction platform for search ads.

While Boxed has featured ads on its site in an effort to “monetize the site” for nearly its entire existence, those ads are designed for the large brands and are sold on a “first come, first served” basis, says Jackson Jeyanayagam, the retailer’s chief marketing officer.

Online-only Boxed, which launched in 2013, says it generated more than $100 million in online sales last year. The average order size is about $100 and includes 10 items. There is no membership fee required for consumers to buy from Boxed, delivery is free for purchases $49 and and packages usually arrive within two days. 95% of orders qualify for free shipping. Boxed also sells its own brand of affordably-priced goods. The startup sells about 1,500 products.

The rollout of a built-in-house, real-time auction platform that allows brands to buy top-of-the-page sponsored search results is aimed at “enabling everyone to compete,” Jeyanayagam says. “It lets smaller suppliers that may not have the budget for a page takeover to target consumers at the right time to try to drive a sale.”

The platform works in much the same way that search-based ad-bidding platforms work on Google, Amazon or other platforms. As an impression loads in a shopper’s browser or app, information about the page and user is passed on to the auction platform, where it is auctioned off to the advertiser that is willing to pay the highest price. That winning bidder’s ad is then loaded nearly instantly.

In offering brands a real-time bidding program, Boxed is competing for ad dollars against some of the biggest names in retail, such as Amazon.com Inc., No. 1 in the Internet Retailer 2017 Top 500; Wal-Mart Stores Inc. (No. 3) on Walmart’s e-commerce sites and apps and on Jet.com; as well as Google. Boxed (No. 326) prides itself on offering a curated product assortment of roughly 1,600 SKUs unlike Amazon, Walmart and Jet, which offer massive selections that can make it difficult for shoppers to find a particular item, making search ads valuable real estate. But even so, Jeyanayagam believes that top-of-the-page placement is still valuable to brands looking to stand out.

“If you’re Coke, do you really want Pepsi above you in search results?” he says. “It is a dog-eat-dog world. Top placement matters.”

Getting a conversion on Boxed can prove particularly valuable because of the retailer’s Smart Stockup service, which predicts when shoppers will most likely run low on particular household products and makes it simple for them to reorder by sending them a reminder about the items they are likely running low on, Jeyanayagam says. “If you can use an ad to get someone to sign up for Smart Stockup then you’ll likely get recurring revenue.”