rhomobile-logoWith the proliferation of multiple competing smartphone platforms, there’s been more talk about the pain that can cause an application developer — Google’s Vic Gundotra has even said Google is “not rich enough” to develop native apps for every smartphone out there. Since launching in March, a startup called Rhomobile has been trying to ease that pain, and now it’s taking even closer aim at big, enterprise-scale companies.

Cupertino, Calif.-based Rhomobile says that rather than building an application for the iPhone, and another for Google Android, and another for the BlackBerry, developers can just use the Rhodes programming framework to create apps (using the HTML and Rails languages) that run across multiple devices. Now it’s also providing the infrastructure — through its RhoSync server — to help enterprises build rich applications that run on iPhone, BlackBerry, Windows Mobile, Symbian and Android devices.

The RhoSync server allows companies to create “sync” applications — in other words, apps that also work offline, then synchronize the data once users are online again. And it just added push notification, allowing iPhone and BlackBerry applications to send messages to users even when the apps are closed. Push notification was one of the big sources of developer excitement about the latest version of the iPhone operating system, but even if you’re just developing for the iPhone, adding push isn’t easy; that’s why companies like Push.io and Urban Airship, which help developers add these services to their apps, are springing up. If you’re trying to build for multiple platforms, the challenge is even more daunting.

Chief executive Adam Blum says sync support has turned out to be more important than he expected. Not only is it being used to support everything from customer relationship management (CRM) apps to FamilyLink, a family-oriented social network, but Blum says he now expects the RhoSync server to make up the bulk of Rhomobile’s revenue (commercial RhoSync licenses start at $5,000 per app), rather than the Rhodes platform or RhoHub, the company’s application hosting service.

I mentioned Google earlier, and publicly at least the search giant has taken a very different approach to the problem of proliferating smartphone platforms — Gundotra has spoken on-stage at the Googe I/O conference and VentureBeat’s own MobileBeat to push for web applications that are accessed from the browsers of all phones, rather than downloadable, native applications built for specific devices. But Blum says all Gundotra’s pro-web-app exhortations haven’t shaken his belief in Rhomobile’s emphasis on native apps.

“I just don’t believe Vic Gundotra was speaking for Google,” he says. “If he was, there’s just no way Google’s investment in Android would be worth it.”

Rhomobile has raised $1 million in funding from vSpring Capital. The company doesn’t track the total number of developers using its tools, Blum says, but there are 1,140 developers on RhoHub, its hosting service. Oh, and the Wikipedia Foundation’s official iPhone app was built using Rhodes.