Zoopla has revealed that over 2,250 branches joined it last year.
Major wins included Carter Jonas, Dacre, Son & Hartley, and Kinleigh Folkard & Hayward.
In a round-up of its achievements for last year, Zoopla said that last year average monthly traffic rose to 58m, with total sessions up 19% compared with 2018.
Over 1.4m people downloaded the Zoopla mobile app which was revamped last August.
There was also a rise in applicant leads to agents, up 18%, with a 41% rise in valuation leads.
Zoopla also refers to a number of new senior hires, and the refocus of its marketing efforts in the coming year, which will result in a 25% increase in marketing spend.
CEO Charlie Bryant said: “2019 was the year of infrastructure where we built the solid foundations necessary for us to reach our goal of re-imagining intelligent home decisions for all.
“With this now in place, 2020 promises to be a year of growth for Zoopla, as we strive for even greater levels of service and customer support.
“We want to be the portal of choice for agents and consumers, but to achieve this we needed to invest in the areas that matter.
“Top of the list was innovation, which is why we’ve put significant resources into developing an industry-leading pipeline of exciting new technology and products, underpinned by a team of experts.
“This renewed focus has led to an increase in sales and valuation leads. This, combined with a pledge of no across-the-board real price increases and a focus on delivering value for agents, means you can see why more agents than ever before are choosing Zoopla.”