The plugin supports external validation. If you have an XSD schema:
Here’s a solid, informative piece you can use or adapt for a blog, documentation, or tutorial. xml tools plugin for notepad
Without a plugin, opening an XML file in Notepad++ is a messy experience. You see raw text, no indentation, and no way to validate whether your closing tags match your opening ones. Here is what the XML Tools plugin solves: The plugin supports external validation