XML Formatter & Validator

Format, prettify, and validate XML data. Detect syntax errors easily.

Size: 0 Bytes
fact_check Reviewed by Senior Editor
verified Reviewed: Jul 28, 2026
update Updated: Jul 28, 2026
commit v2.0.0
schedule 5 min read

lightbulb When to use this tool

  • check_circle Formatting a minified SOAP API response to inspect its envelope, headers, and body structure during API integration debugging.
  • check_circle Validating an Android layout XML file or Spring configuration file before committing to identify well-formedness errors.
  • check_circle Reading the internal XML structure of a .docx, .xlsx, or .pptx file by renaming it to .zip, extracting, and formatting the XML files.
  • check_circle Formatting an RSS or Atom feed to inspect its structure and verify required elements are present.
  • check_circle Minifying a production XML config file to reduce file size before deploying to a server.

Why use our tool?

Browser's Native DOMParser — Spec-Compliant Validation

Specific Error Messages — Not Just 'Invalid XML'

Format and Minify Both Directions

Configurable Indentation

Your XML Never Leaves Your Browser

How it works

1

Paste your raw or minified XML into the input area.

2

The tool validates the XML immediately. If well-formed, it formats the output. If invalid, it displays the specific parser error.

3

Select your indentation preference: 2 spaces, 4 spaces, or tabs.

4

Click 'Copy Formatted XML' for the beautified version, or 'Minify' for the compact single-line version.

5

For SVG files, paste the SVG source directly — SVG is XML and formats correctly with this tool.

Examples

science Formatting a SOAP Response

science Detecting a Missing Closing Tag

Frequently Asked Questions

What is the difference between XML validation and XML well-formedness? expand_more
Well-formedness is a structural requirement: every XML document must have exactly one root element, all tags must be properly closed (including self-closing tags with />), attribute values must be quoted, and special characters must be escaped (&, <, >, ', "). A well-formed XML document can be parsed without error. Validation is an additional step that checks whether the document conforms to a specific schema (DTD, XSD, or RELAX NG) — whether the right elements appear in the right order with the right attributes. This tool checks well-formedness only. Schema validation requires the schema document itself and is not currently performed.
Does this tool work with SVG files? expand_more
Yes. SVG (Scalable Vector Graphics) is an XML-based format. Paste the SVG source code and the formatter will parse, validate, and format it identically to any other XML document. This is useful for inspecting or editing SVG files generated by design tools like Figma, Adobe Illustrator, or Sketch, where the exported SVG may be minified or contain redundant attributes.
Is my XML sent to a server for formatting? expand_more
No. Formatting uses the browser's native DOMParser API, which runs entirely in your browser's local context. No XML content is transmitted externally. This is particularly relevant for SOAP payloads containing authentication data, config files with credentials, or proprietary data structures.
What does 'parsererror' mean in the output? expand_more
When the browser's DOMParser cannot parse your XML, it returns a document containing a parsererror element rather than the actual XML content. This element's text content describes the problem — for example: 'error on line 5 at column 12: Opening and ending tag mismatch: database line 3 and config'. The line and column numbers help you locate the error in the original input.
Can I format XML with namespaces (xmlns declarations)? expand_more
Yes. The XML specification fully supports namespaces (xmlns:prefix declarations), and the browser's DOMParser handles them correctly. Namespace-prefixed elements (soap:Envelope, xs:element, etc.) format correctly, and namespace declarations are preserved in the output. Undeclared namespace prefixes will cause a parsererror — all prefixes used in the document must be declared.
What is the difference between XML and HTML? expand_more
HTML is a specific language for web pages with a predefined set of elements and rules. XML is a meta-language for defining custom data structures with any element names you choose. HTML is more permissive — browsers auto-correct many errors. XML is strict — any well-formedness violation causes a parsing failure. HTML5 also has an XML-serialized form called XHTML. Both are structurally similar (tags, attributes, nesting) but XML has stricter rules: all tags must close, attribute values must be quoted, case is significant.
Can this tool handle very large XML files? expand_more
Performance depends on your browser's XML parsing speed and available memory. The DOMParser builds a complete in-memory DOM tree, which for large files (1MB+) may consume significant RAM. For files of a few hundred kilobytes, formatting is near-instantaneous. For files above 5MB, consider using a local tool like VS Code (with the XML extension), xmllint (command-line), or Notepad++ with an XML plugin.

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