Is it possible to build any application without Azure Active Directory involvement for Office 365 REST API?

Question

Is it possible to build any application (console, windows store, WPF, MVC, Web API, Android, iOS etc.) that consumes the Office 365 REST API without Azure Active Directory involvement?

So far that does not seem possible without Azure Active Directory. But there are many app on Windows, Android and Applet app store that can be connected to Office 365 and pull the user contacts. So how do they do that?

Answer 1

the new and recommended way to register an app for OAUTH and consume the Office365 REST apis is through this url devs.apps.microsoft.com

This has been created to allow people without an Azure Account to consume Office365 apis.

Answer 2

You have to distinguish between not requiring Azure AD and not requiring an Azure subscription. Every Office 365 subscription automatically gets an Azure AD tenant behind the scenes. As of today, many of the development features are offered only through the Azure portal, but that's just how things have been factored. For example, if you use Visual Studio 2015 you can create and modify apps that use Azure AD and Office 365 without the need for any Azure subscription. In the old approach, you would use the Live SDK for getting contacts for consumer users - as described in https://msdn.microsoft.com/en-us/library/hh826535.aspx. In an upcoming update to the services, you will be able to use the exact same API for both consumers and organizational users - see https://dev.outlook.com/RestGettingStarted for a good introduction to the new capabilities.