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XML Validator

Validate XML with a real parser, surface well-formedness errors, and keep markup private in your browser.

Results

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Status
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Details
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How to use this validator

  1. Paste your XML snippet or document.
  2. Run validate to parse with DOMParser.
  3. If invalid, fix the reported tag/character near the shown line/position and re-validate.

Rules & checks

Uses the browser’s DOMParser to enforce well-formed XML (single root, proper nesting, closing tags).

Surfaces the first parser error message to speed up fixes.

Works best on snippets up to a few hundred KB for snappy parsing; larger files still run locally.

No network calls—markup never leaves your browser.

Inputs explained

  • XML content

    Paste UTF-8 XML with a single root element. Escape ampersands (&) and keep payloads modest for browser speed.

When to use it

  • Validate sitemaps, RSS/Atom feeds, and web manifests before publishing
  • Check XML API payloads or SOAP envelopes during integration tests
  • Lint CMS exports or template fragments from legacy systems
  • Prep XML before running XSD or schema validation in CI

Common errors

  • Mismatched or missing closing tags
  • Multiple root elements instead of one
  • Unescaped ampersands or special characters
  • Attributes missing quotes
  • Improperly nested elements

Limitations

  • Well-formedness only; does not validate against XSD/DTD or business rules.
  • Entity resolution and external resource fetching are not performed.
  • Very large XML may be slow in the browser—use CI for multi-MB feeds.
  • Does not fetch remote URLs; paste content directly.

Tips

  • Ensure a single root element wraps everything.
  • Escape special characters (&, <, >) in text nodes.
  • Quote all attribute values.
  • Keep large files small in-browser; run full validation in CI for big payloads.

Examples

Valid: simple note

  • <note><to>Ada</to><from>Grace</from><body>Hello</body></note> -> Well-formed

Valid: sitemap entry

  • <url><loc>https://example.com/</loc><lastmod>2024-01-01</lastmod></url> -> Well-formed

Invalid: mismatched closing

  • <note><to>Ada</note> -> Invalid (closing tag mismatch)

Invalid: unescaped ampersand

  • <title>Fish & Chips</title> -> Invalid (use &amp; instead of &)

Deep dive

This XML validator uses the browser’s DOMParser to enforce well-formed XML and surface the first parser error so you can fix broken tags or unescaped characters fast.

It runs entirely client-side for privacy; for deeper XSD or DTD checks, pair it with schema validation in CI after the syntax passes.

FAQs

Is my XML uploaded or stored?
No. Parsing stays in your browser and clears on refresh.
Do you validate against XSD or DTD?
No. This checks well-formedness only. Run XSD/DTD validation in CI if required.
How big can the XML be?
Keep it to a few hundred KB for fast results. Multi-megabyte feeds are better suited to CI tools.
Does it resolve external entities?
No. External entity fetching is not performed; it’s a safety measure and keeps validation local.
Can I use it offline?
Yes. Once loaded, it runs offline because everything is client-side.

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