xmlserializer is a Node.js library that serializes DOM subtrees or documents into XML/XHTML, serving as a drop-in replacement for browsers' XMLSerializer. It handles HTML documents generated by parse5 and regular browser DOMs, addressing limitations in XML 1.0 compliance and HTML to XML conversion. This tool is designed for developers working with XML/XHTML serialization in Node.js environments, particularly those needing consistent behavior across different browsers and platforms.