Beautify, validate, and minify XML with syntax highlighting. Errors shown with exact message. Nothing uploaded — all processing in your browser.
XML (eXtensible Markup Language) is a text-based format for storing and transporting structured data. Unlike HTML, XML has no predefined tags — you define your own. It is widely used in configuration files, SOAP web services, RSS feeds, SVG, DOCX files, and data exchange between systems.
XML formatting (beautifying) adds consistent indentation and line breaks to make XML readable. Raw or minified XML is a single line with no spacing. A formatted version indents nested elements, making it easy to read and edit.
A well-formed XML document follows these rules: it has exactly one root element, all tags are properly closed, tags are correctly nested (no overlapping), attribute values are quoted, and special characters are escaped (<, >, &, ', "). This validator checks all these rules.
HTML defines fixed tags for web pages (div, p, h1, etc.) and browsers are lenient about errors. XML is customizable — you define your own tags — and is strict: even one unclosed tag or unescaped character makes the whole document invalid. XML is for structured data; HTML is for web page rendering.
An XML namespace (xmlns) prevents tag name conflicts when combining XML from different sources. For example, <book:title> and <movie:title> can coexist using namespaces. Namespaces are declared as xmlns:prefix="URI" attributes on elements.