FormatDrop
Document Format

XML

Extensible Markup Language

XML (Extensible Markup Language) is a text-based format for storing and transporting structured data, published as a W3C recommendation in 1998. Unlike HTML (which has fixed tags), XML lets you define your own tags to describe any kind of data. XML uses a tree structure of elements (opening and closing tags), attributes (key-value pairs inside tags), and text content. It was the dominant data format for web services and enterprise systems throughout the 2000s, and remains essential for SOAP APIs, RSS/Atom feeds, SVG images, Microsoft Office documents (DOCX, XLSX, PPTX are ZIP files containing XML), and countless configuration formats.

What is XML?

An XML document starts with an optional declaration (`<?xml version="1.0" encoding="UTF-8"?>`) followed by a single root element containing all other elements. Elements can have attributes (`<user id="42">`), child elements, and text content. XML supports namespaces (using `xmlns` declarations) to avoid tag name conflicts when mixing vocabularies. Schema validation via XSD (XML Schema Definition) allows strict validation of document structure and data types. XSLT (Extensible Stylesheet Language Transformations) can transform XML documents into HTML, other XML formats, or plain text.

XML pros and cons

Advantages

  • Supports namespaces — mix different XML vocabularies in one document without conflicts
  • XSD schema validation — strict, standardized type checking and structure validation
  • Comments supported — document the data inline
  • XSLT transforms — transform XML to HTML, other XML, or any text format
  • Both attributes and child elements — two ways to represent data

Limitations

  • Verbose — opening and closing tags for every element increase file size
  • More complex to parse than JSON in most programming languages
  • No built-in list type — arrays must be represented as repeated elements
  • Namespaces add complexity for simple use cases
  • JSON has replaced XML for most REST APIs and web services

When should you convert XML files?

Keep XML when working with SOAP web services, RSS/Atom feeds, SVG images, Office Open XML (DOCX/XLSX), Android resources, Maven/Spring configurations, or legacy enterprise systems. Convert XML to JSON when building REST APIs, JavaScript applications, or NoSQL data pipelines that work naturally with JSON. Convert XML to CSV when the XML contains simple tabular data you need in a spreadsheet.

All FormatDrop conversions run entirely in your browser — no file upload, no server processing. Your files stay on your device.

XML FAQ

What is the difference between XML and HTML?
HTML and XML both use angle-bracket tag syntax, but they serve different purposes. HTML has a fixed set of tags defined by the HTML standard (div, p, span, etc.) and browsers are lenient about errors. XML lets you define your own tags for any data structure and requires strict well-formedness (every tag must be closed, attributes must be quoted, etc.). XHTML is HTML written to follow XML rules. SVG and MathML are XML vocabularies embedded in HTML documents.
How do I convert XML to JSON?
Many programming libraries handle XML-to-JSON conversion: Python's `xmltodict` library (`pip install xmltodict`), Node.js's `xml2js` or `fast-xml-parser` libraries, and command-line tools like `xq` (based on jq). Online tools like FreeFormatter.com handle small files. Note that XML's attributes and text nodes don't map perfectly to JSON — different libraries make different choices about how to represent them.
Is XML still used in modern software?
Yes, extensively. Microsoft Office files (DOCX, XLSX, PPTX) are ZIP archives containing XML. Android app layouts and resources are XML. Maven pom.xml, Spring application context files, and countless Java frameworks use XML configuration. SVG is XML. RSS and Atom feeds are XML. SOAP web services (still common in banking, insurance, healthcare) use XML. While JSON dominates REST APIs, XML remains essential in many domains.

More formats

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