In a sign of the listing portal’s growing influence, hit more than 100 million unique visitors in September, sparking a 1,290 percent annual increase in traffic. Now the portal is second only to Zillow.

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In a monumental sign of the real estate listing portal’s growing influence, CoStar Group’s hit over 100 million unique visitors in September, besting and Redfin in monthly unique visitor traffic for the first time since acquiring the portal nearly three years ago, the company announced Monday.

That level of traffic made the No. 2 most visited listing portal during the month of September, second only to listing giant Zillow. reported 74 million monthly unique visitors on average and Redfin reported 52 million monthly unique visitors on average during the second quarter of 2023, according to company earnings filings.

CoStar founder and CEO Andy Florance told Inman that the company’s achievement was no accident since a lot of time and energy went into getting the portal to where it is today.

Andy Florance | Photo credit: CoStar

“I know we’ve surprised everybody,” Florance said.

“Probably a lot of people are adjusting their perceptions right now. We’ve been at this for a long time. We have more experience than anybody in real estate technology and real estate, for sure. We have a long track record of building up traffic on various sites and going from acquiring companies that are No. 5 or No. 6 in traffic and building them up to No. 1. We reimagined from scratch. From day one, we’ve taken very experienced teams in SEO, SEM, UX and content, and this has been our single highest priority for the last 12 to 18 months. I probably literally work on this seven days a week.”

Across all of CoStar’s network of U.S. real estate portals, including its rental sites, the company brought in 160 million unique visitors in September, more than and Redfin’s traffic combined, a press release from CoStar noted.

Florance added that the company’s “your listing, your lead” business model, whereby home shoppers looking at listings are directly connected with a property’s listing agent, was one of the company’s biggest unique value propositions that also helps streamline the home shopping process for consumers.

“It’s a much cleaner experience if people or consumers come to the site if they are interested in the home, engaged in a home, being able to simply click through to the person who has the listing and knows more about the listing than anyone else is a better consumer experience,” Florance said. “So I think we’re getting credit for that.”

In addition, Florance said, the company is “saving agents billions of dollars in commission splits referrals, as we should,” referring to the fact that real estate agents often pay for referrals and promotions on sites like Zillow or’s significant traffic, which was up a whopping 1,290 percent year over year, also comes at a time when the very nature of buyer agent commissions is under scrutiny with the ongoing bombshell commission lawsuits, suggesting that the portal finds itself in a secure position during this uncertain time for the industry.

“The first-generation real estate portals have been leveraging this threatened buyer-broker commission rule to divert listing leads from all the agents in the market to a small handful of agents who are then required to split their commissions with the portal,” according to a statement. “Many agents and brokers strongly resent that model. Now that is one of the most heavily trafficked portals, there is a strong and viable alternative for lead generation available to agents that does not require usurious commission splits. Unlike the first-generation portals,’s business model is not negatively impacted by the potential end of the buyer-broker commission rule.”

CoStar closed its acquisition of in May 2021 for $156 million. The online real estate information company had also acquired Homesnap at the end of 2020, but by June 2023, decided to sunset the brand in order to transition users to Homes, the more dominant of the two.

CoStar, meanwhile, is in the midst of legal action against Homesnap’s founder, Guy Wolcott, alleging he hired away former Homesnap employees from CoStar in order to help him with a new business venture, after those employees had become privy to proprietary CoStar trade secrets.

As far as what’s next for the real estate portal, Florance said the company has its eye on the No. 1 slot currently occupied by Zillow.

“We are 100 percent focused on being the No. 1 most heavily trafficked site,” Florance told Inman. “I think we’re sober and understand how much hard work that is and we are committed to that. We’d love it if everyone continued to underestimate us, but nonetheless, we’re going to push it forward. We want to be No. 1.”

Update: This story was updated after publishing to clarify that’s and Redfin’s website traffic were average monthly figures recorded during the second quarter of 2023, according to company earnings filings.

Email Lillian Dickerson

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