Microsoft has some very high ambitions for Windows 10. The company announced today at its annual Build conference that it wants to have the new operating system running on one billion devices within the next three years, a feat that is unheard of for just about any platform. But how will they get there?

It helps that Windows 10 is going to be a free upgrade for Windows users. But that doesn’t address a key downside of the Windows ecosystem: The platform, which has more than 500,000 apps thus far, still doesn’t have nearly as many apps as iOS (1.2 million, at last count) or Android (1.3 million). Developers are slow to build out Windows versions of their new apps, and Microsoft plans to change that.

How do you fix a problem like this? Microsoft’s bet is on giving developers streamlined, cross-platform-friendly tools to build apps as easily as possible. And it looks like it may be onto something.

During the Build event, Microsoft said that it will enable several pathways into the Windows Store. Developers can repackage their web apps, built using plain old HTML5 and JavaScript and easily turn them into Windows apps. Devs can do the same thing with .NET and Win32 code. But the news that got the biggest reaction from the crowd this afternoon is the ability to do the same with C++/Java and Objective C. That means developers will be able to seamlessly port their iOS and Android apps to Windows 10.

This is potentially huge. By removing the friction from the process of getting apps into the Windows Store, these new software development kits could help position Windows 10 as a more viable competitor to Google’s and Apple’s operating systems.

This all sounds exciting to room full of coders, but what about everyday users? For the rest of us, these tools mean one thing: more apps. That’s a huge selling point for users, who may like the idea of Windows 10, but have thus far been turned off by the dearth of apps available.

Windows 10 is an ambitiously cross-platform endeavor, which is important. Whereas Apple has slowly inched toward unifying iOS and Mac OS X, Microsoft is going all out: Apps built for Windows 10 will be able to run on phones, tablets, desktops, and televisions, via Xbox 360. By making that cross-platform experience seamless for developers and invisible to users, Microsoft is hoping to make the platform more attractive to users. Did your work computer just get upgraded to Windows 10? Do you love it? Well, you can get the same experience on a phone or a tablet too. Just sayin’.