XML Formatter & Validator

How to Use the XML Formatter & Validator

This free online XML tool formats and validates your XML data in one step. Paste your XML into the input area, choose your preferred indentation, and click "Format & Validate". The tool will check for well-formedness and display either the formatted output or clear error messages.

Features

• XML validation using the browser's built-in DOMParser
• Pretty-printing with customizable indentation (2 or 4 spaces)
• Clear error messages for malformed XML
• Self-closing tag detection for empty elements
• Attribute preservation and proper formatting

What Makes Valid XML?

Valid (well-formed) XML requires all tags to be properly closed, attributes to be quoted, elements to be properly nested, and a single root element. Unlike HTML, XML is strict about syntax. A missing closing tag or unescaped ampersand will cause a parse error. This tool uses the browser's native XML parser to detect all such errors.

Common XML Errors

The most common XML errors include unclosed tags, mismatched tag names, unescaped special characters (use &amp; for &, &lt; for <, &gt; for >), missing quotes around attribute values, and multiple root elements. This validator will identify these issues and help you fix them quickly.

XMLフォーマッター & バリデーターの使い方

XMLデータをテキストエリアに貼り付け、インデント幅を選択して「整形 & 検証」ボタンを押すと、 整形されたXMLが出力されます。パースエラーがある場合は明確なエラーメッセージが表示されるため、 問題箇所をすばやく特定・修正できます。全ての処理はブラウザ内で完結し、データは外部に送信されません。