One Outlook REST API - your favorite platform - 400+ million users

With the simplicity of REST, you can use your favorite language and IDE, write your app once, and capture 400 million monthly active users, and tens of millions active Office 365 users.

Start with choosing a language for your app—Node, Python, Ruby, Swift—just to name a few. Write the code, take advantage of new, streamlined services to register and authorize the app, and access user's mail, calendar, and contacts data on or Office 365. You can use the same Outlook REST API for Android, iOS, Windows, on the web, mobile, and desktop. There's no need for any specialized Exchange knowledge!

Get started

  1. Register your app. Registration takes only a minute.

  2. Start coding and implement REST API calls.

Streamlined services

There's just one simple process for and Office 365: register and get dynamic user authorization to access users’ mail, calendar, and contacts.

Take an early look at the following services in preview status:

  • Azure Active Directory admin center

    Use a Microsoft account or Microsoft 365 subscription account to register your app. It takes only a few steps to identify your app for and Office 365.

  • v2 endpoints:

    Use these common authentication endpoints to sign users in with their personal accounts, or business or school credentials, and request authorization for access. Instantly expand the reach of your app!


Use these preview services when:

  • Rewriting existing apps that use the Windows Live API. Windows Live API has been deprecated for Plan to accommodate changes to these services over their preview period.
  • Creating new and Office 365 apps that access mailbox data.

Plan to upgrade in-production Office 365 apps after the preview period is over.

Outlook REST API via Microsoft Graph

Use one common REST endpoint...{version} make all Outlook REST API calls in the following APIs:

For more information and a comparison between the Graph endpoints and the Outlook API endpoints, see Compare Microsoft Graph and Outlook endpoints.