ToolFeather

XML Validator

Check whether your XML is well-formed, see the exact error and location if it isn't, and pretty-print valid XML with clean indentation — all in your browser.

XML Validator

Drop an .xml file here or click to choose

🔒 Your XML is checked in your browser with the built-in parser — nothing is uploaded.

🔒 Nothing you enter is sent anywhere or stored. All processing happens in your browser.

Features

Well-formedness check

Uses the browser's built-in XML parser to confirm your tags are closed, nested and quoted correctly — a true valid-XML check, not a guess.

Pinpoints the error

If the XML isn't well-formed, you get the parser's message describing what's wrong, so you can find the broken tag fast.

Pretty-print valid XML

Format well-formed XML with clean, consistent indentation to make nested elements readable.

Open a file or paste

Drop in an .xml, .svg or .rss file, or paste the markup directly.

Private and in-browser

Validation and formatting run on your device — your XML is never uploaded.

How it works — in four simple steps

No signup, nothing to install — it all runs in your browser.

Step 01

Paste or open your XML

Drop an XML file onto the box, or paste the markup into the text area.

Step 02

Validate

Press Validate — a green tick means well-formed; otherwise you'll see the exact parser error.

Step 03

Fix any error

Use the error message to locate a missing closing tag, stray character or unquoted attribute, then re-check.

Step 04

Format it

Press Format to pretty-print valid XML with clean indentation.

How it works

Well-formed XML follows the basic syntax rules: every opening tag has a matching closing tag, tags are properly nested, attribute values are quoted, and there's a single root element. This validator checks exactly that using the browser's own XML parser — the same engine browsers use — so if it passes here, standard tools will read it too.

Paste your XML or open a file and press Validate. If it's well-formed you get a green tick; if not, you get the parser's error message describing what went wrong and roughly where, so you can find the stray tag or missing quote. Press Format to pretty-print valid XML with consistent indentation, which makes nested structures far easier to read.

This checks well-formedness (syntax), which is what most people mean by "valid XML". It doesn't validate against a specific DTD or XSD schema. Everything runs in your browser — your XML is never uploaded.

Examples

Paste a config or RSS snippet to confirm every tag is closed and nested correctly.
Format a minified one-line XML document into a readable, indented tree.

Frequently asked questions

What does it mean for XML to be valid or well-formed?
Well-formed XML obeys the syntax rules: matching and properly nested tags, quoted attribute values, and a single root element. This tool checks well-formedness — what most people mean by a 'valid XML checker'.
Does it validate against a schema (DTD/XSD)?
No. It checks well-formedness (syntax), not conformance to a specific DTD or XSD. Schema validation needs the schema file and a dedicated validator; well-formedness is the first thing to get right.
How do I find where my XML is broken?
Press Validate and read the error message — the browser's parser reports what it choked on (for example an unclosed tag or mismatched element), which points you to the problem.
Can it format or beautify XML?
Yes. If the XML is well-formed, press Format to pretty-print it with consistent indentation so nested elements are easy to read.
Is my XML kept private?
Yes. It's checked and formatted entirely in your browser using the built-in parser, so nothing is uploaded.