XML Validator

About this tool

Almost every XML failure in practice is one of four things: a tag that is never closed, tags closed in the wrong order, an attribute value without quotes, or a bare ampersand that should have been an entity. All four produce parser messages that name a symbol rather than a cause, which is why the report rewrites them into a sentence about the document.

When the document does parse, the report describes what it found — the root element, how many elements and attributes there are, and how deeply they nest. That is usually enough to confirm you have the file you expected before spending time on it.

This is well-formedness, not schema validation. A document can be perfectly well-formed and still be wrong for its purpose, and the report says so rather than letting the word valid be read as a broader promise than it is.

How to use this tool

1. 1

   Paste XML, upload a file, or drop one onto the editor.

2. 2

   Press Validate.

3. 3

   If it fails, use the reported line and column to go to the problem.

4. 4

   If it passes, read the summary to confirm the root element and size are what you expected.

Key features

• Well-formedness checking with the line and column of the first error
• Parser messages rewritten into plain descriptions of the cause
• An excerpt of the offending line shown alongside the error
• Element, attribute and nesting-depth counts when the document passes
• The encoding declared in the prolog reported when present
• Runs entirely in the browser, so the document is never uploaded

Example

<inventory>
  <item sku="TENT-2P">
    <quantity>34
  </item>
</inventory>

The XML has a tag that is never closed or is closed
out of order. Expected closing tag 'quantity'
(opened in line 3, col 5) instead of 'item'.

Line 4, column 3

Good to know

Frequently asked questions