XML allows creation of documents spanning several namespaces. These namespaces must be available to the XPath query system otherwise you will be unable to locate the elements.

XMLNS is a special map which allows you to associate prefixes with namespaces.

Also refer to Any XPath lookup in an XML document returns no results→.

Mapping

By default there are a few defined namespaces in the property files. They are as follows:

set %XMLNS:soapenv% http://schemas.xmlsoap.org/soap/envelope/
set %XMLNS:xsd% http://www.w3.org/2001/XMLSchema
set %XMLNS:xsi% http://www.w3.org/2001/XMLSchema-instance

This is also the syntax you'd use to add a new namespace. These prefixes are then available for use in XPath, such as //xsi:type/@value.

Mode Limited

This mechanism is limited only to the internally controlled modes such as raw requests, email, direct URL modes, and a few others.

In particular, these prefixes are not available in the browser backends HTMLUnit and Selenium. We have no idea how we would get that working.