This is more than double the amount of visitors the site had in both February this year and March 2017.
Visits are the individual sessions on the property market's website or mobile application measured by Google Analytics, the company said.
Despite being only a month of data, OnTheMarket is "very encouraged" by the growth and expects this momentum to continue through a combination of increasing marketing and the increase in branches signing up and listing properties.
The real estate agent also said it continues to grow its customer sales team, looking to double their team between early February's listing and the end of April.
It is hoped, it said, this will increase its capacity in the field to engage directly with "the thousands" of small and medium sized agent firms which make up the majority of the market.
Chief Executive Ian Springett said: "We are very pleased to have delivered a major uplift in visit traffic in the first full month post-IPO. The early signs show that even before the full ramp up of marketing spend, we have been able to generate significant increases in our levels of traffic to the site."
"We now look forward to a period of investment in marketing to build effective consumer engagement with the portal and will deploy more resource to proven marketing activities to attract more and more property-seeking consumers to OnTheMarket," he added.
Shares in OnTheMarket were trading at