Rebtel, a private Swedish provider of Voice-over-Internet-Protocol (VoIP) announced new software to permit developers to design new apps into smarphones.

The six-year-old company that claims 17 million customers said the Rebtel Voice Platform for both iOS and Android phones should enable adding VoIP applications to any other app in only 15 minutes.

The new app is “a game-changing tool,” said Rebtel CEO Andreas Bernstrom. The free tool should benefit thousands of content developers seeking to integrate voice into all manner of aps, from gambling to game-playing, the company said.

Rebtel executives plan to describe the new service Wednesday at the Appnation developers conference in San Francisco.VivFone, a private developer in Palo Alto, Calif., said it would be among the first companies to integrate its customer-research management (CRM) app with the Rebtel platform.

Backed by venture capital firms, Rebtel claims to be the No. 2 VoIP provider behind Skype, acquired last year by Microsoft Corp. (NASDAQ:MSFT), the No. 1 software developer, for $8.5 billion.

Rebtel said it expects 2012 revenue around $80 million. It didn't provide earnings figures.

Shares of Microsoft rose 48 cents to $27.42 in Tuesday trading.

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