Skip to content
Format XML

Browser-based — nothing to install

Validate XML Online, error by error

Paste or drop an XML document up to 5 MB and get immediate feedback right in your browser. Well-formed markup shows element and attribute counts; broken markup shows the exact error type, line, column, and the source line that caused it. No signup, no upload, nothing to install.

  • 100% free
  • No signup
  • Up to 5 MB
  • Line + column errors
  • Runs in browser
Formatted XML

The formatted result appears here.

Paste XML, drop a file, or press Ctrl+V anywhere on this page.

How to validate XML online

Three steps — paste, check the result, fix and repeat. No install, no account.

  1. Load your XML into the online validator

    Paste XML into the left panel, drag a file onto the page, or press Ctrl+V (⌘V on Mac) to load from the clipboard. The online validator accepts documents up to 5 MB — .xml, .xsd, .xsl, .svg, .rss, .plist, and every other XML dialect.

  2. Check the validation result

    Results appear instantly below the panels. A well-formed document shows the element count, attribute count, and maximum nesting depth. A broken document shows the error type (mismatched tag, unclosed element, duplicate attribute, etc.), the exact line and column, and the offending source line.

  3. Fix errors and re-validate

    Edit the XML directly in the left panel — validation re-runs on every keystroke, so you can work through a chain of errors without clicking a button. Once the document is valid, switch to Beautify to clean up the indentation.

Technical specifications

ChecksWell-formedness: tag matching, attribute quoting, duplicate attributes, unterminated constructs
Accepted inputAny XML — .xml, .xsd, .xsl/.xslt, .svg, .rss, .atom, .wsdl, .kml, .plist, .config, pom.xml
Error detailError type, line number, column number, and offending source line
Maximum document size5 MB, about 150,000 lines
Also formatsBeautify (2 spaces, 4 spaces, or tab) and minify to one line
Processing locationYour browser — the XML is never uploaded to a server
PriceFree, no signup, no limit on the number of documents
Works offlineYes, once the page has loaded
Device supportDesktop, laptop, tablet, and phone — any modern browser

Frequently asked questions

Can I validate XML online without installing anything?

Yes. This validator runs entirely inside your browser — no download, no extension, no command-line setup. Open the page, paste your XML, and the result appears on the status bar below the editor.

What does this online XML validator check?

It checks XML well-formedness as defined by the XML 1.0 specification: matching open and close tags, quoted attributes, no duplicate attributes on the same element, properly terminated comments, CDATA sections, and processing instructions. It does not validate against an XSD or DTD schema.

Is the online XML validator free?

Completely free. There is no signup, no daily limit, and no document cap. Validate as many files as you need.

Is my XML uploaded to a server?

No. The parser runs in JavaScript inside your browser tab. Nothing is sent over the network, which also means validation keeps working after you go offline.

What is the file-size limit?

5 MB per document, roughly 150,000 lines of typical markup. A 2 MB file validates in well under a second on a modern laptop. Above 5 MB the tool asks you to split the document to avoid freezing the browser tab.

Can I validate SVG, RSS, SOAP, or Maven pom.xml online?

Yes. Every XML dialect is parsed the same way — SVG artwork, RSS and Atom feeds, SOAP envelopes, WSDL, XSD schemas, Android layouts, and .plist files. Namespace prefixes, CDATA, entities, and processing instructions are all handled.

How is this different from the XML formatter?

The formatter re-indents valid XML to make it readable. This page does that too, but the focus is on the error report: you get the error type, line number, column, and the source line itself. If you only need pretty-printing, the homepage at format-xml.com has a formatting-first interface.

Does the validator work on a phone or tablet?

Yes. It is a responsive web app that works in any modern browser on any device. On smaller screens the input and output panels stack vertically.

Why validate XML online?

Desktop tools like xmllint require installation and a terminal. IDE plugins add steps when all you need is a quick syntax check on a config snippet or an API response. An online validator removes every barrier: open a tab, paste, and see the result in under a second.

This validator goes further than most — it runs a custom XML parser in JavaScript so your document never leaves the browser, and it pinpoints errors with the exact line, column, and source context instead of a generic “parse error” message. It keeps working after you disconnect from the internet, too.

Once your XML passes validation, you can clean it up right here — switch to Beautify for readable indentation or Minify to strip whitespace. For a formatting-first workflow, try the XML formatter on the homepage. Need to shrink the file? The XML minifier collapses it to a single line.

Where your XML is processed

Everything happens in the browser tab you are reading this in. The document you paste is parsed and checked by JavaScript on your own machine and is never uploaded, logged, or stored — which is also why validation keeps working after you disconnect from the internet.