The Office 365 APIs are REST services that provide access to Office 365 data, such as: mail, calendars, and contacts from Exchange Online; files and folders from SharePoint Online and OneDrive for Business; users and groups from Azure Active Directory.

Whether you want to incorporate the richness of Office 365 data into your app, or create a custom experience within Office 365 itself we will assist you with that. Office 365 API functionality is also available through the Microsoft Graph, a unified API that includes APIs from other Microsoft services such as Outlook, OneDrive, OneNote, Planner, and Office Graph, accessible through a single endpoint and with a single access token. It is recommended to use the Microsoft Graph in your apps when possible.