How to Access the Source for an Email Message in

How to view the source of an email message in

Person at laptop

With, you can access the source for any email message and find out, for instance, what path it took to arrive in your account (using the headers) or what causes the left column to seem a wee bit off (using the HTML code).

Instructions in this article apply to and Outlook Online.

Access the Source for an Email Message in

To view the full source behind an email in

  1. Select or open the email.

    The inbox.
  2. Select More actions (the 3 horizontal dots).

    Selecting a received email in
  3. Select View message source.

    Viewing More actions in
  4. View and scroll through the contents.

    Viewing the source of an email in
  5. When done, select Close.

How to Interpret Message Headers

Inspecting headers can lead to some valuable insights about a message:

  • Received: Shows the mail servers that processed the message on its journey from source to destination.
  • Return-Path: Displays the Reply to address, which may be different than the From address.
  • Authentication-Results: References whether (or to what degree) the sender's email server verified the sender's credentials.
  • Date: Lists the date the message was originally transmitted by the sender.
  • From: Shows the email address, and often the display name, of the person who sent the message.
  • Reply-To: Displays the address used to reply to the message. May not be the same as the address of the sender.
  • Message-ID: Identifies the tracking number of the email.
  • Precedence: Used by different servers in different ways, and some don't use it at all.
  • List-Unsubscribe: Identifies the email address used to unsubscribe from the mail list the message sourced from.
  • X-Spam-Score: Identifies what the server thinks the likelihood is that the message is spam. If the score falls above a given number, the message may be automatically moved to the spam folder.

There are many approved types of email headers, and many headers are either inconsistently used or controversial among the guardians of internet standards. Despite the diversity of information, these headers share useful information about the message, its sender, and its path to your inbox.