Microsoft and Facebook are taking a significant step toward making password fatigue a thing of the past. Microsoft has officially integrated Facebook login APIs into Windows 8/8.1 and Windows Phone 8.

Microsoft corporate VP and chief evangelist Steve Guggenheimer and Facebook developer relations executive Dhiren Patel announced the added support in separate blog posts last week as part of the companies’ ongoing development partnership.

Developers can now enable consumers to log into an app with a single click or tap, reusing Facebook credentials stored on the device. The implementation also funnels other app interactions through Facebook, like sharing high scores and events, and playing games against Facebook friends.

To access the API documentation, each company has provided blog posts for Windows and Windows Phone developers:

Windows 8 and 8.1 developers:
Microsoft documentation
Facebook documentation

Windows Phone developers:
Microsoft documentation
Facebook documentation

Facebook login for Windows 8 is ready for wide app use, and Windows Phone 8 login will be in beta for the next 60 days or less as developers give feedback.