The group cited a challenging UK property market and revised down the top end of its revenue forecast for the year.
Purplebricks now expects revenue to come in between £165m-175m over the year, from a previous prediction of £165m-185m.
Revenue in the UK was up by 39% to £48.3m in the six-month period, compared to the previous half year.
And the agent completed on £5.4bn of UK property, up from £4.6bn.
Taking bigger share of UK market
Purplebricks said it now has a 74% share of the so-called hybrid estate agent market.
Earlier this month, online rival Emoov announced it had gone into administration.
And in September, estate agent Connells axed its online agent Hatched and declared the internet-only or hybrid model was “fundamentally flawed”.
Purplebricks said it expects no short-term improvement in the “challenging” UK property market conditions.
But the agent added it was confident of taking further market share from competitors in the coming six months.
International income accounted for almost a third of group income, which increased by 75% to £70.1m.
The group has expanded its US business to operate in seven states, and has also entered the Canadian, German and Australian markets.
Michael Bruce, group chief executive, said: “Our UK business continues to make good progress, with strong sales growth, market share gains and a step-up in both profitability and positive cashflow.
“It is this strength that will see Purplebricks emerge stronger from the ongoing industry shakeout, which is expected to continue to expose under-capitalised traditional and online competitors.
“Purplebricks has led industry change and through our strategy of relentless innovation will continue to do so.
“We are always looking to improve the customer experience and with over £100m of net cash, we are uniquely placed to do so, investing in technology and first class people.
“We remain confident that our UK success will be replicated internationally and that we will deliver substantial value for our shareholders.”