HEATKEYS

The Stylus Studio XML Editor is an innovative XML IDE providing advanced XML development tools for XML, XSL, XSLT, XML Schema, DTD, SOAP, WSDL, SQL/XML, XML mapping, Web services and XQuery, simplifying XML data integration.

Free source code and tutorials for Software developers and Architects.; Updated: 7 Nov 2012

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!

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.

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

XPath over XML Schema Project Homepage

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.

The World Wide Web Consortium (W3C) is an international community where Member organizations, a full-time staff, and the public work together to develop Web standards.

JetBrains, creator of the best Java IDE - IntelliJ IDEA - is a technology-leading software development firm specializing in the creation of intelligent development tools.