XML validation

{{Refimprove|date=May 2010}}

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.{{cite web

|work=Extensible Markup Language (XML) 1.1

|title=Well-Formed XML Documents

|url=http://www.w3.org/TR/2004/REC-xml11-20040204/#sec-well-formed

|date=2004

|publisher=W3C

}} A valid document also respects the rules dictated by a particular DTD or XML schema.{{cite web

|title=Constraints and Validation Rules

|work=XML Schema Part 1: Structures Second Edition

|date=2004

|publisher=W3C

|url=http://www.w3.org/TR/xmlschema-1/#concepts-schemaConstraints

}} Automated tools – validators – can perform well-formedness tests and many other validation tests, but not those that require human judgement, such as correct application of a schema to a data set.