HEATKEYS

A web-based XML validator. Can be used for free. Validates XML files, prompts the user for referenced files (e. g., XSD), shows good error messages.

HTML XHTML CSS JavaScript XML XSL ASP SQL ADO VBScript Tutorials References Examples

W3C

Online tools for developers, including formatters (JSON, XML, HTML, SQL, etc.), minifiers (JavaScript, CSS), validators, compactors and many more!

For Focused .NET/XML and Web Services Training Visit the XML for ASP.NET Developers Website: http://www.xmlforasp.net

The web, animation and midlets developers resource.

Tools to allow simple testing of xpath expressions online on live XML content

SourceForge.net. Fast, secure and free downloads from the largest Open Source applications and software directory

The Microsoft Support home page is your support portal for Microsoft products. Download updates and find top issues, error messages, and troubleshooting tips for Windows XP, Windows Vista, Windows 7, Office 2010, the 2007 Microsoft Office system, and...

Altova XMLSpy XML editor, plus other leading XML, data management, UML, and Web services software tools for application, web site, and database development, data conversion, and more.

oXygen XML Editor is a cross platform XML Editor providing tools for XML authoring, XML conversion, XSL, XSLT, XQuery, XML Schema, DTD, Relax NG and Schematron development, SOAP and WSDL.