What Is XML?
XML (eXtensible Markup Language) is a markup language designed to store and transport data. Unlike HTML (which defines how data looks), XML defines what data means through custom tags. It remains widely used in enterprise systems, RSS feeds, SOAP web services, Android layout files and Microsoft Office formats.
XML vs JSON
JSON has largely replaced XML for REST APIs because it is lighter and easier to parse. However XML has advantages that keep it relevant: it supports attributes alongside element content, has native namespace support, and is better suited to document-centric data (like Word documents or SVG files).
Common XML Errors
Unlike HTML, XML is strict. Common errors include:
- Unclosed tags — every opening tag must have a corresponding closing tag
- Attribute values without quotes — all attribute values must be quoted
- Illegal characters — characters like < and & must be escaped as
<and& - Missing XML declaration — while optional,
<?xml version="1.0" encoding="UTF-8"?>is best practice
Why Format XML?
Minified XML (no whitespace or indentation) is efficient for transmission but unreadable for humans. Formatted (beautified) XML uses consistent indentation to make the structure clear. Both represent identical data.
Format and Validate XML Free
Our XML Formatter formats, validates, minifies and converts XML to JSON — all in your browser with no server upload required.
