Data from the portal shows that 63% of properties were listed as SSTC within 30 days of first being listed for sale during April.
The figure is up from 54% a year ago but a slight decrease when compared with 64% in March 2022.
In contrast, the proportion of homes listed for sale more than 30 days ago that were SSTC within 60 days has increased from 15% in March to 16% in April 2022, while the time on the market figure for 90 days has increased from 5% to 8% over the same period.
Scotland was the fastest selling region during April, with 79% of homes SSTC within 30 days of first being listed for sale, according to OnTheMarket.
Greater London had the lowest number of properties which were SSTC within 30 days at 50%.
In April 2022, the region with the most number of properties which had taken 120 days or longer to SSTC was also greater London at 15% compared with Scotland where the equivalent figure was 5%.
The figures form part of OnTheMarket’s latest Property Sentiment Index.
It found that 76% of active buyers in the UK were confident that they would purchase a property within the next three months, while 82% of sellers were confident that they would sell their property.
Buyers are also confident about obtaining the mortgages they need despite recent interest rate rise.
More than a third of buyers already had a mortgage agreement in principle in place in April, with only 1% of movers reported to be ‘very worried’ about mortgage availability.
The average asking price of listings through the portal hit £390,661 last month, up from £378,915.
Jason Tebb, chief executive of OnTheMarket said the lack of stock is sustaining house price growth.
He said: “The number of properties newly listed for sale is slowly increasing and supply/demand economics suggest that if this continues, price growth will moderate.
“If there’s more choice of properties for sale and buyer numbers remain consistent, or even start to drop off, there could be a levelling off in activity and prices.
“However, the fundamental lack of stock at the present moment means that values will hold at a certain level.
“While there may be further challenges to come, for now our data shows strong confidence from both buyers and sellers, which is continuing to fuel the UK housing market.
“There are many reasons why people need to move and there are plenty looking to do so. This is particularly true in the regions outside the major conurbations as they look their best right now with spring leaves on the trees – one of the reasons why spring/summertime is a natural time to sell.
“The challenges of the past two years have ingrained a sense of positivity in the housing market which shows no signs of slowing and as such continues to thrive as serious property seekers get on with the business of moving.”