Mobile radio app TuneIn revealed that it now has 40 million monthly active listeners in 230 countries, as it announced $25 million in venture funding.

The company added that its service passed one billion listening hours during the first four months of 2013, with more than 227 million listening sessions in March alone.

TuneIn plans to use the funding to accelerate the development of new technologies and support its expansion.

The investment round has been led by Institutional Venture Partners (IVP) with input from existing investors Sequoia Capital, Google Ventures and General Catalyst Partners. IVP general partner Jules Matz will join the TuneIn board of directors as part of the investment deal.

“We will use this funding to leverage our momentum, with particular focus on growing ad revenues for our broadcast partners,” said TuneIn CEO, John Donham.

TuneIn Live, a major redesign of the platform adding a more personalised way to find radio stations, music and events, was launched in March, resulting in increased user engagement.

The company is also boosting its expertise by hiring senior staff, including Google’s former head of capital markets, Axel Martinez, who recently joined as CFO.