XML Formatter & Validator

Paste your XML to format, validate, or minify it. Uses the browser's native XML parser — 100% client-side.

Input XML
Output
Paste XML above to format or validate it.

How to Use the XML Formatter

  1. Paste your XML into the input area on the left (or top on mobile).
  2. Choose a format mode — 2-space (default), 4-space, or Minify.
  3. View validation results — the status bar shows whether your XML is valid and counts elements and attributes.
  4. Copy or download the formatted XML using the buttons above the output panel.

What This XML Formatter Does

This free online XML formatter uses your browser's native DOMParser API to parse and validate XML. The DOMParser is the same engine browsers use to process HTML and SVG documents, making it a reliable and standards-compliant validator. Unlike regex-based tools, it catches all well-formedness errors: unclosed tags, attribute quote violations, invalid characters in names, and missing root elements.

Validation Features

  • Well-formedness check — uses DOMParser to detect any XML syntax errors
  • Error messages — shows the parser error message in the status bar for easy debugging
  • Element count — counts all elements in the parsed document tree
  • Attribute count — counts all attributes across all elements

Formatting Features

  • 2-space indentation — compact but readable format
  • 4-space indentation — more spacious format for presentations or documentation
  • Minify — removes all whitespace between tags for the most compact representation
  • XML declaration preservation — keeps <?xml version="1.0"?> declarations

Common XML Use Cases

XML is still widely used in many domains even though JSON has largely taken over for REST APIs. Android application resources are written in XML — layouts, strings, drawable definitions, and manifest files. Maven and Gradle build systems use XML for POM files and configuration. Office document formats (DOCX, XLSX, PPTX) are actually ZIP archives containing XML files. RSS and Atom feeds are XML. SOAP web services use XML envelopes. SVG graphics are a dialect of XML. And many enterprise data exchange formats — HL7 FHIR in healthcare, XBRL in finance, and GML in geographic information — are XML-based.

XML Well-Formedness vs. Validity

There are two levels of XML correctness. A well-formed XML document follows the syntactic rules of the XML specification: exactly one root element, all opening tags closed, proper nesting, quoted attribute values, and no illegal characters. A valid XML document is well-formed AND conforms to a schema — either a DTD (Document Type Definition) or an XSD (XML Schema Definition). This tool checks well-formedness using the browser's DOMParser. Schema validation against a specific XSD requires a server-side validator or a desktop application like Oxygen XML Editor. For most debugging needs, well-formedness checking is sufficient.

XML vs. JSON for APIs

If you are designing a new API and choosing between XML and JSON, JSON is almost always the better choice for modern REST APIs. JSON is more compact, easier to read, maps directly to JavaScript objects, and has broad library support in every programming language. XML's advantages — namespaces, attributes, mixed content, schema validation, and XPath querying — are important in specific domains but rarely needed for typical API payloads. Need to convert between formats? Try our JSON Formatter or YAML to JSON Converter.

Frequently Asked Questions

XML (eXtensible Markup Language) is a flexible text format for storing and transporting structured data. Unlike HTML, XML has no predefined tags — developers define their own element names. XML is widely used in web services (SOAP, RSS, Atom), Android resource files, Maven build configs, and enterprise data exchange formats.
No. This XML formatter runs 100% in your browser using the built-in DOMParser API. Your XML data never leaves your machine. There is no server-side processing, no logging, and no data collection.
Well-formed XML follows the structural rules of the XML specification: every opening tag must have a closing tag, elements must be properly nested, attribute values must be quoted, and there must be exactly one root element. This tool uses the browser's native DOMParser to check whether your XML is well-formed and reports any parse errors.
JSON is simpler, more compact, and maps naturally to JavaScript objects. XML supports attributes, namespaces, mixed content, and formal schema validation. JSON has largely replaced XML for REST APIs, but XML remains standard for SOAP web services, SVG, Android resources, and many enterprise data formats.
This tool uses the browser's native DOMParser to parse your XML. If the XML is malformed, the parser returns a parseerror document containing the error message and location. The tool detects this and shows the error in the status bar. If parsing succeeds, it counts elements and attributes, then formats the output with proper indentation.