The W3C has a online validator for XML Schemas at http://www.w3.org/2001/03/webdata/xsv. Since W3C is the source of the XML Schema spec, their validator should be trustworthy.
The W3C has a online validator for XML Schemas at http://www.w3.org/2001/03/webdata/xsv. Since W3C is the source of the XML Schema spec, their validator should be trustworthy.