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

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

W3C

Free Online Tools for Software Developers

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.

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

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

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.