XML validation is the process of checking a document written in XML (eXtensible Markup Language) to confirm that it is both "well-formed" and also "valid" in that it follows a defined structure. A "well-formed" document follows the basic syntactic rules of XML, which are the same for all XML documents. A valid document also respects the rules dictated by a particular DTD or XML schema, according to the application-specific choices for those particular .
In addition, extended tools are available such as OASIS CAM standard specification that provide contextual validation of content and structure that is more flexible than basic schema validations.
XML Checker, Validate, Test