XML Notepad is an open-source XML editor written by Chris Lovett and published by Microsoft. The editor features incremental search in both tree and text views, drag/drop support, IntelliSense, find/replace with regular expressions and XPath expressions, and support for XInclude. The editor has good performance on large XML documents and has real time XML schema validation. The editor also features an HTML viewer for displaying XSLT transformation results and a built-in XML comparison tool.
The program's source code was made available on CodePlex on 20 April 2007, and moved to GitHub in April 2016.