When you are authoring XML documents that conform to a schema, you can validate those documents using a third-party XML authoring tool like Altova's XMLSpy. You can open your XML document in XMLSpy and validate it against an XSD file containing your schema.
To Validate an XML Document Using XMLSpy
When XMLSpy warns you that your XML may be pretty-printed, click OK.
XMLSpy inserts a schemaLocation attribute at the root element of your XML. This attribute points to the location of your XSD file.
If your XML file is valid, XMLSpy will display a "This file is valid" message at the bottom of the window containing your XML. If the XML is invalid, XMLSpy will display a message that indicates what problem may be causing the XML to be invalid.