SOAP Header element

SOAP is a simple XML-based protocol that enables applications to exchange information over HTTP.

Or more simply: SOAP is a protocol for accessing web services.

SOAP Header element syntax

The optional SOAP Header element can contain application-specific information about the SOAP message (such as authentication, payment, etc.).

If the Header element is provided, it must be the first child of the Envelope element.

SOAP Header element example

<?xml version="1.0"?>
<soap:Envelope
xmlns:soap="http://www.w3.org/2001/12/soap-envelope"
soap:encodingStyle="http://www.w3.org/2001/12/soap-encoding">
<soap:Header>
  <m:Trans xmlns:m="http://www.w3schools.com/transaction/"
  soap:mustUnderstand="1">234
  </m:Trans>
</soap:Header>
...
...
</soap:Envelope>