When Nokia teamed up with Microsoft to compete with smartphone rivals Apple and Google, the company was putting something valuable in danger: the loyalty of the programmers who create apps for the Nokia ecosystem.

Following the companies announced their partnership last week, many die-hard Nokia programmers posted comments in forums and blog posts, expressing feelings of betrayal while threatening to code for Android instead.

“Developers are outraged because they feel that Nokia has betrayed them and sold them to Microsoft,” said Andres Kruse, a programmer who makes apps using the Qt toolkit that will not be supported on Nokia’s Windows phones.

Developers have been a crucial resource for each major technology company’s media ecosystem. Programmers’ apps ultimately determine what a company’s product can do, and compelling apps can serve as a significant attractor for consumer sales. Apple, Google, Nokia and Microsoft have aggressively recruited developers to create apps for their platforms as though they’re soldiers going to war.

Many consider Nokia’s Symbian operating system to become outdated when compared with Apple’s iOS and Google’s Android, however the Finnish phone company has cultivated a development community for over a decade. One of the most popular programming toolkits produced by Nokia is Qt (pronounced cute), a wide open source application framework that can create software that works on multiple platforms.

Microsoft and Nokia a week ago cut a deal, in which Nokia would adopt Windows Phone 7 since it’s primary mobile operating system. The agreement reportedly cost Microsoft billions of dollars.

One major side effect involved in the Nokia-Microsoft partnership is the fact that going forward, Qt will not be supported on Nokia’s Windows phones. Nokia will continue to sell Symbian phones supporting Qt within the next two years, and Nokia claims it’ll still develop Qt, but eventually the company will transition to Windows Phone 7 as its primary OS.

“By shifting our future smartphone strategy from Qt there is a strong sense of frustration from those who have committed to Qt for mobile development,” Nokia’s Aron Kozak said in a article. “We sympathize and that we understand…. There is no magical statement we can make that proves things will be great, however we will attempt to maintain open communication once we progress.”

However, Kruse said he felt pressured to determine whether to recreate apps for Windows Phone 7, or to take an entirely new route such as Android.

“This is a company where it feels like they’ve been doing everything for them and today their company is capitulating,” said Gartner analyst Michael Gartenberg, regarding Nokia developers who reacted negatively towards the Microsoft partnership. “You can imagine when Steve Jobs came back to Apple in 1997, if he explained ‘We’re done with Macintosh, we’re just likely to build Windows PCs,’ you would’ve seen the same reaction in the Apple community.”

Brian Watson, Microsoft’s director of developer evangelism for Windows Phone 7, explained that Nokia and Microsoft opted against supporting Qt to be able to keep up with the integrity from the Windows Phone platform. Apps developed for all Windows Phones should be made with Microsoft’s native toolkits such as Silverlight and XNA.

“It can be a tough pill to swallow … but it’s for the better,” Watson said.” Worthwhile developer will learn new languages coming along. It’s about finding the right tools to find the job done.”

However for Qt developer Kruse, Nokia’s switch to Windows Phone 7 means greater than just learning new programming languages. It’s a matter of the potential risks and charges involved in coding for one platform and then being located in. By comparison, with Qt, Kruse could make an app that runs on Nokia phones, Windows and Macs with minimal effort.

“In our case we make software for disabled people, and the marketplace is so small that we simply cannot afford to develop for a platform whose success is as simple as no means certain,” Kruse said. “Qt might have taken that risk away. Now we will have to go for Android. A minimum of there we all know this isn’t going away.”

Watson said Microsoft understands the importance of the Nokia developer community, and also the company works tough to keep your community loyal see how to avoid from the new partnership. To recruit developers for Windows Phone 7, Microsoft has handed out free devices for programmers to try their apps, or even offered to fly them to the Microsoft campus to get a quick studies, Watson said.

“Our goal is making developers happy, making developers successful, making developers famous and rich,” Watson said. “They’re a very scarce resource and … I don’t want to lose them. We’re likely to be very creative with things we can do.”