First published on TECHNET on Dec 14, 2017 This post is a contribution from Manish Joshi, an engineer with the SharePoint Developer Support team
The purpose of this blog is to walk through the process of calling the Outlook Mail API to send messages in Office 365 and Outlook.com. These guide focuses on the OAuth and REST requests and responses. It will cover the sequence of requests and responses that an app can use to authenticate and send an email messages with file attached from a SharePoint Online list item.
The previous two steps involved creating an email message and adding an attachment. The final step is to send the email message. This is a post request to the endpoint https://outlook.office.com/api/beta/me/messages/<<messageID>>/send . The request and response body are empty in this case. The status will be "202 Accepted" if the email message has been successfully sent