XML Formatter

XMLの整形、圧縮、検証。

入力

OUTPUT

Indent:

Beautify & Minify

Format or compress XML with proper indentation.

Validate

DOM-based XML validation with error messages.

Copy Result

One-click copy to clipboard.

Client-side

All processing in your browser. No data uploaded.

XML Formatterについて

The XML Formatter is a free, browser-based tool for beautifying, minifying, and validating XML documents. XML is used everywhere — REST API responses, SOAP web services, configuration files, RSS/Atom feeds, SVG graphics, Android layouts, Maven POM files, and countless data exchange formats. When XML arrives as a compact single-line string or is poorly indented, understanding its structure is time-consuming and error-prone. The beautifier parses the tag hierarchy and adds consistent indentation so that every parent-child relationship is immediately visible. Prolog declarations (<?xml version="1.0"?>), self-closing tags, and XML comments are all handled correctly without disrupting the indent level. The built-in validator uses the browser's native DOMParser to check for well-formedness errors such as unclosed tags, mismatched element names, illegal characters, and missing attribute quotes — displaying the exact error message so you can fix it quickly. The minifier strips all inter-element whitespace to produce the most compact representation. Everything runs in your browser, so your XML data — which may include API keys in attributes, private records, or internal configuration — is never sent anywhere.

XML Formatterの使い方

Paste your XML content into the left input panel.
Select the indentation size (2 or 4 spaces) from the dropdown at the bottom.
Click "Beautify" to format the XML with proper indentation and line breaks.
Click "Validate" to check whether the XML is well-formed — any errors will be displayed in red in the output panel.
Click "Minify" to compress the XML into a single compact line.
Click "Copy" to copy the output to your clipboard.

よくある質問

What kind of XML validation does this tool perform?

The tool checks for XML well-formedness using the browser's built-in DOMParser. This catches unclosed tags, mismatched tag names, illegal characters, and malformed attribute syntax. It does not validate against an XSD or DTD schema.

Can I use this for SVG files?

Yes. SVG is a subset of XML, so SVG files can be pasted in, beautified, validated, and minified using the same tool.

Does it handle XML namespaces?

Yes. Namespace declarations (xmlns:prefix="uri") are treated as regular attributes and are preserved correctly during formatting.

Is this safe for sensitive XML data like API responses?

Yes. All processing runs entirely in your browser using client-side JavaScript. Your XML data is never uploaded to any server.

What is the difference between well-formed and valid XML?

Well-formed XML follows the basic syntax rules of XML (correct tag nesting, closed tags, etc.). Valid XML additionally conforms to a specific schema (XSD or DTD). This tool checks well-formedness only.