How to Access the Source of an Email Message in Outlook.com

Get behind the scenes of an email message

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

Instructions in this article apply to Outlook.com.

To View the Full Source Code of an Email in Outlook.com

  1. Select or open the email.

    The Outlook.com inbox.
  2. Select More actions (the three horizontal dots).

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

    Viewing More actions in Outlook.com.
  4. View the contents.

    Viewing the source of an email in Outlook.com.
  5. When you're done, select Close.

How to Interpret Message Headers

Inspecting headers can lead to valuable insights about a message.

Email header information

Commonly used headers include:

  • 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 on which the sender originally transmitted the message.
  • 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. This is not always 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; some don't use it at all.
  • List-Unsubscribe: Identifies the email address you can use to unsubscribe from the mail list from which the message originated, if any.
  • X-Spam-Score: The estimated likelihood that the message is spam. If the score falls above a given number, the message might be automatically moved to the spam folder.

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