

Last fall, Microsoft aggressively recruited Mr. Weingarten to convince him to build his nutrition app Fooducate for its Windows Phone. Microsoft proposed putting a Fooducate engineer in Tel Aviv through a weeklong boot camp, and offered a new Windows-based Nokia phone for software testing.

Yet despite the enticements, Fooducate skipped the boot camp and chose not to develop a Windows Phone app.

"We decided to focus our energies on the bigger platforms" of Apple's iPhone and Google's Android, said Mr. Weingarten, the 41-year-old chief executive of Fooducate. He said he plans to develop for Windows Phone eventually.


Last year, Microsoft hosted more than 850 sessions world-wide to coach developers on Windows Phone software design, more than triple the number the year before. Microsoft also has sped up the process of launching apps, expanded ways app makers can make money from selling their wares on Windows Phone and cut checks to some developers to help pay for apps.


A man walks past a banner of a Windows phone at the Mobile World Congress, the world's largest mobile phone trade show, in Barcelona, Spain, in February. Associated Press

Microsoft is desperate to break the stranglehold of iPhone and Android. Its 18-month-old Windows Phone, which powers devices made by Nokia Corp. and Samsung Electronics Co., has just a 3.9% share of smartphones in the U.S., compared with 50.1% for phones powered by Google's Android software and 30.2% for Apple's iPhone, according to comScore Inc.

Apps are a major attraction for smartphone buyers, but there are only about 70,000 available for Windows Phone, compared with a half a million or more for Android phones and iPhones.

On a recent day, of 60 top iPhone apps, only 13 were available for Windows Phone. The holdouts included popular apps such as Zynga Inc. 's "Words With Friends" and Pandora Media Inc. 's digital-music service.


To promote the Windows Phone brand to consumers, the Redmond, Wash., company plans a significant marketing push soon, Mr. Myerson said, though he declined to give details. The Windows Phone group recently hired an advertising executive behind Verizon Wireless's "Can You Hear Me Now" campaign.





The company's app tools are easy to use, they say, and Microsoft is more attentive than other companies. Jake Poznanski and Sam Kaufmann, who quit their software-developer jobs last fall to develop Windows Phone apps, said Microsoft replied within a couple of days when they complained about a snag in Windows Phone's mobile advertising system.

Mr. Poznanski said when he reached out to Inc. about a question with a try-before-buying feature of that company's app store, Amazon never got back to him. Amazon declined to comment on specific conversations with developers, but the company said it has a team of people dedicated to answering inquiries from developers.

Microsoft also is incorporating input from app developers into Windows Phone updates. In recent months, Microsoft also said it was opening Windows Phone app sales in more than a dozen countries including China. And Microsoft has followed other app companies in paying developers upward of $100,000, or paying a third-party company to develop a Windows Phone app on their behalf.

Some developers are starting to buy in to Microsoft, in part because they are growing disenchanted with the prospects of struggling BlackBerry maker Research In Motion Ltd. (A RIM spokeswoman said "There has been a clear commitment from BlackBerry to developers.")

The Weather Channel said starting in November, it reassigned employees designing software for BlackBerry to Windows Phone apps. Cameron Clayton, Weather Channel's executive vice president of digital, said just under 10% of the company's 100,000 daily app downloads are coming from Windows Phone, up from less than 0.5% three months ago as Weather Channel signed deals to come preloaded on Windows Phone devices.

"Versus a year ago, they have a shot now," Mr. Clayton said of Microsoft. At the same time, he conceded, "This is a war for developers time and attention, and Apple and Android are winning."

—Will Connors contributed to this article.

Write to Shira Ovide at and Ian Sherr at