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

Free cross-platform web-based Online XML Editor, runs on Linux, Windows, Mac, FireFox, Chrome, IE. Edit XML schema or document. No user registration required.

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

W3C

The web, animation and midlets developers resource.

XML Check is free online XML and Sitemap validation service and software. It does strict scheme validation, finds all document structure issues and reports errors with line and column numbers

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

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.