SAN FRANCISCO (AP) — Microsoft figures one way to get people psyched about Windows 10 is to make sure there are plenty of cool features and apps for smartphones and tablets that use the new operating system.

That's why the tech giant is making its case Wednesday before an army of software developers who may be crucial allies in its campaign to build enthusiasm among consumers for the next version of Microsoft's flagship operating system, coming later this year.

While Microsoft has already previewed some aspects of the new Windows, a parade of top executives will use Microsoft's annual "Build" conference to demonstrate more software features and app-building tools, with an emphasis on mobile devices as well as PCs. Ultimately, they're hoping to win over people who have turned to smartphones and tablets that run on rival operating systems from Google and Apple.

During the three-day conference, Microsoft may also show off new Windows smartphones or other devices and reveal more details about such tech initiatives as the company's new Spartan web browser; its Siri-like digital assistant known as Cortana; and the HoloLens, a futuristic "augmented reality" headset that projects three-dimensional images in a wearer's field of vision.

But perhaps most importantly, this year's conference is an opportunity for Microsoft to persuade an audience of more than 5,000 techies and independent programmers that it's worth their time to create new apps and programs for Windows 10. Experts say Microsoft needs a rich variety of apps if it wants to appeal to people who are increasingly using mobile gadgets instead of personal computers.

"Getting developer buy-in is absolutely the crucial thing," said J.P. Gownder, a tech industry analyst at Forrester Research. He said Microsoft has struggled with a "chicken-and-egg" problem, in which developers have been reluctant to build mobile apps for Windows because relatively few people use Windows phones and tablets.

Microsoft hopes it has solved that problem by designing Windows 10 so it's easier for developers to build "universal" apps that work on a variety of Windows devices, from phones to PCs and other gadgets, Gownder said.

The company also has a big carrot to wave in front of those developers: Microsoft has already said it will release Windows 10 as a free upgrade to people who now have PCs or other gadgets running the previous two versions of Windows, provided they upgrade in the coming year. The offer could create a huge new audience of Windows 10 users in a relatively short time, Gownder said.

Microsoft has not said exactly when Windows 10 is coming, and some analysts are hoping the company will announce a release date at the conference, along with details about how it will distribute future upgrades.

CEO Satya Nadella and other executives have hinted they'd like to move away from the old notion of selling each new version of Windows as a separate product. Microsoft's had early success in selling its Office productivity software on a subscription basis, in which customers pay an annual fee to use programs like Word, PowerPoint and Excel.

Nadella is presiding over a major overhaul of a company that once dominated the tech industry, in the days when PCs were king. He has redesigned some of Microsoft's most popular programs for mobile devices and invested in new "cloud-computing" services, in which businesses pay to use software that's housed in Microsoft's data centers.

Microsoft still relies heavily on selling traditional software for PCs and corporate computer systems. But its latest quarterly earnings report, issued last week, offered some signs that the decline in that business is slowing, while Microsoft's cloud-computing business is growing rapidly. The news drove Microsoft's share price up 10 percent in one day. The stock has continued to climb, closing Tuesday at $49.15.

Nadella will discuss the company's strategy and financial performance at a gathering of Wall Street analysts in San Francisco later on Wednesday afternoon.