XML Validator
Validate XML and locate every error
Check XML well-formedness in real time. Mismatched tags, unclosed elements, and unescaped characters are flagged at the exact line and column — all processed privately in your browser.
🔒 100% private — your document is processed entirely in your browser and is never uploaded, logged, or stored.
Find the broken tag in seconds
When an XML document won’t parse, the cause is usually a single misplaced character.Indentio reports the exact line and column, names the problem — a mismatched closing tag, an unescaped ampersand, a duplicate attribute — and, where it’s safe, offers a one-click fix.
The rules it enforces
- One root element wrapping the whole document.
- Properly nested, closed tags — every
<tag>needs a matching</tag>. - Escaped special characters in text and attribute values.
- Unique attribute names per element, each with a quoted value.
Works with any XML dialect
SVG, RSS, Atom, XSD, WSDL, sitemaps, config files — they’re all XML, so you can validate and format any of them here. Upload a file or paste the markup directly.
Frequently asked questions
How do I validate XML online?
Paste your XML into the editor. Well-formedness is checked as you type, and any error is underlined in red at its exact line and column with an explanation.
What is “well-formed” XML?
Well-formed XML has exactly one root element, every tag properly closed and nested, special characters escaped (&, <, >), and no duplicate attributes. This validator enforces all of those rules.
Does it validate against a DTD or XSD schema?
Not yet — it checks well-formedness, which is what most people need. Schema (DTD/XSD) validation is on the roadmap.
Is my XML kept private?
Yes. Everything runs in your browser; your XML is never uploaded or stored.