OnTheMarket achieved a record level of traffic of more than 10m visits in September – a rise of 79% year on year.
Last September it recorded 5.6m visits.
Throughout last month, the portal also delivered a record number of leads to agents.
Chief executive Ian Springett said: “This latest record achievement for traffic is another sign of just how much progress OnTheMarket has made throughout 2016.
“Since January, we have significantly grown the overall number of offices listing on the website ranging from many high-profile, multi-branch firms to a large number of smaller independent agents.
“Consumers are also becoming increasingly aware of the new-to-market properties which many of our agents are choosing to display at OnTheMarket.com 24 hours or more ahead of any other portal.”
He said the portal “has proved that it is thriving and continues to grow”.
OnTheMarket measures its traffic using Google Analytics.