Header

An email header is the information that tells email recipients and servers where the email has come from and where it should go.

The documentation that accompanies the body of an email message, the header contains information on the email and the route it has taken across the Internet. Email readers display the "to" (identity of the recipient) and "from" (identity of the sender) in the inbox.

More information:

• Managing headers with SMTPAPI
• Managing headers with the Web API
• Transactional Email Templating